RECORD: Darwin, C. R. 1832.07-08. Zoological diary: Monte Video. CUL-DAR30.70-76. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Richard Darwin Keynes in Zoology notes (2000, F1840). Revised and supplemented here by Christine Chua to correspond to the manuscript images. Edited by John van Wyhe 6-7.2022. RN1

NOTE: Original transcription reproduced with permission of Richard Darwin Keynes, the Syndics of Cambridge University Library, English Heritage (Down House Collection) and William Huxley Darwin.


70

Rio de Janeiro ─ M Video

1832 July

Biphora allied to (e) Plate 5: — Body transparent, spherical, incurved at the poles.— Length about .4.— Fig 1: represents it as seen under microscope, (K) (Beroc) from extreme transparency everything lies in one plane.— Through centre is a most (b) thin tube, open at each extremity, enlarged in middle & one half much broarder.— This in Fig 2. is seen containing a membranous sack, much broarder & capacious posteriorly, & divided by longitudinal slit through its whole length. On the upper side the edge has power of expanding & contracting (NB this organ may lie above the central tube & not in it; the extreme transparency not allowing the ascertainment of this) This upper edge is thickened in its upper half & coloured pink.—

(m) At the point (a)2 in Fig: 2 there was visible a pulsation, similar to what I have before seen in this animals tribe.— In Fig 1: on each side is a highly delicate bag, not attached to outer coat of animal.—

(a) Within this (Fig: 3) is an opake membrane to which is attached a mass of vermiform tubes, precisely resembling intestines.—

(k) These had the power of moving themselves.— The spherical outer covering of animal has eight longitudinal bands (one magnified Fig 4), which send out transverse fibres & appear to act as muscles.—

(d) I cannot understand the organization of this animal.— I could not see Branchiæ:— The thickened pink edge can hardly be considered as the Liver.— Perhaps the pear-shaped bags may be the ovaries.—

[70v]

(a) 3300 471

(b) 331.— The situation being comparatively lofty & the stones large, the habitat must be very dry.—

(c) November 20th.— The summer is now far advanced & yet I find this animal under stones.— is it Nocturnal? I found it also at Buenos Ayres in same sites. This species differs most strikingly from that of Rio de Janeiro in its shorter depressed body.— I may mention in this place, having found on an Agave a true Limax4, but unfortunately lost it.— it would appear to have been hitherto not found in S America.—

June. Maldonado.— I have found this latter animal & immense numbers of the Vaginulus.

71

Monte Video

1832 August 15th

Vaginulus Not uncommon under stones on the Mount. Length varying in my specimens from three inches to 1/2; breadth (of largest) .8.— Measures taken when crawling; when at rest & its head retracted under mantle it was only 1.8 in length & .9 in breadth.— Mantle much flattened, oblong, of a uniform breadth; bluntly rounded at each extremity; rugosely punctured; projecting much laterally over foot:— foot narrow, caudal extremity appearing under mantle when animal crawls.— Mouth retractile under mantle; feelers short, superior rounded at end, bearing eyes, length .2; inferior appearing forked; the lower fork with extremities pointed; feelers coloured yellowish.— Foot & under side of mantle white.— Mantle pale dirty yellow, thickly mottled with purplish dark brown, so arranged that 2 pale irregular streaks are left tracing the form of foot.— The brown is sometimes so thick as become of a uniform colour.— The youngest specimen was the darkest coloured.— Anal & Branchial orifice? Mouth.— large (Novr 20th) These animals were found on summit of Mount (450 feet above the sea), where there is only herbage & no trees.—

[in margin:] Also Buenos Ayres found under stones.— This species differs from the Rio Janeiro species in its shorter & more depressed form

Planaria (b) Inhabits same site as the last animal under dry stones on the Mount.— The description of Planaria (Page 50) agrees with this in so many particulars, manner of walking &c &c that it may be considered as generic & the following as only specific. Body slightly flattened, length (when crawling) 1.9: breadth .1

[in margin:] organ [2 words illeg] Eyes scattered at regular intervals on anterior part of body

[71v]

(a) 332

(b) The family Tremato to which Planaria belongs is characterized by having beneath its body, "des organes en forme de ventouses".— perhaps the grooved surface at anterior extremity corresponds with this: although I never saw it used for any purpose, but as a sort of a feeler to direct its way.—

No. 643 [illeg] contain 1 1/2 in spirits

rather less than 2/3 of length from anterior orifice, posterior 25/100 from anterior orifice.

Seen in [illeg] Ocelli very numerous, minute & at regular intervals at anterior extremity, in groups of two or three at sides body

72

Monte Video

1832 August 15th

Planaria (b) Anterior extremity grooved beneath, much pointed, body gradually widening from this to the tail which is bluntly pointed.— Back coloured rich "umber brown" with a central dorsal narrow streak of "broccoli brown" reaching its whole length.— Beneath, of this latter colour.— On the under surface were two white spots, where (from the exact resemblance to the Planaria of Rio) I have no doubt there are apertures.— I believe I could perceive one.— I could perceive as formerly (page 51) the vibratory motion in the slimy surface of whole animal.— it occurs was seen wherever there was a gleam of light & it made no difference whether this was direct or reflected.— The animal seems to find presence of air to be necessary on the under surface.— Salt water (brine) killed & almost dissolved the body.— Animal not uncommon.— X

Planaria (a) Habitat &c same as last.— Body throughout of a more uniform narrowness.— (not tapering so much from head to tail) more cylindrical: length 1.3; breadth about .07.— Colour above pale dirty yellow with 2 dorsal stripes of "umber brown", which become narrower & unity at each extremity.— These Planariæ when first taken were rather inactive & were found on the earth beneath stones.—

[72v]

(a) Sept: 6th.— Lat 40° S.— I observe that during this night, Crustaceæ of the Schiropodes & some other Macrouris, appear to abound on the surface, whilst during the day few can be taken. This applies to animal (Page 73):— as certainly many crustaceæ are luminous may this not explain help to explain the phenomenon of the luminous sea.—

(b) Octob: 23d — Lat: Sea wonderfully luminous; milky when seen in the mass; sparkling in numerous bright spots when seen in a tumbler; but I could not succeed in making by agitation, water in a watch glass show luminous particles, although certainly abundant in it.— The breakers & bows & wake of ship, i.e. when air acts on water, is luminous: this was after a heavy sea — Can this by destroying numbers of small animals be the cause:—

(c) The dung in shape is rounded oval; when dried & burnt smells like, but pleasanter, to Cedar wood. This animal is very abundant in Rio St. Lucia: the hides are valuable being very tough: but the meat is very indifferent eating.— Cap. Paget of the Samarang killed 45 of these animals.— For more particulars V 192.

73

1832

Cavia capybara (c) Copied Shot August 15th one of these animals, when I first saw it was on the rocks under the Mount. They do not appear to congregate in herds as described in other places.— perhaps the want of shelter may influence them.— The specimen2 was a female & weighed 98 pounds.— Girth 3ft..2: Length from tip of snout to the tail 3ft..8½: Height from toes to top of shoulder 1ft..9.

Luminous Sea (a) (b) August 22nd. between Points St Antonio & Corrientes: the sea was very luminous: light, pale, sparkling, but not as in Tropics either milky or in flashes.— The Luminous particles passed through fine gauze.— In the water were some minute Crustaceæ of the genus Cyclops. I should not be surprised if these added to the effect.— During the day the sea has abounded with Dianœa.— & I find these when kept in water till they are dead render it luminous.— can this be the cause of the appearance in the ocean.—

Polype? undescribed At page (2) this animal is described, but having opportunity thoroughly to examine one, I found some curious facts.—

[in margin:] July 1834: Found some 4 feet beneath surface: off Valparaiso.—

August 24th. Lat.: 37°.26′ S Long: 56°.58′ W: Sounding 10 Fath: This specimen agreed with those found at the Abrolhos.— PL 1. Fig 1.2 I have drawn the posterior half of animal.— The tail, or that part which the central intestinal tube does not penetrate is filled with a fine granular pulpy matter. With .3 focal distance lens, a longitudinal division & one on each side of this might be seen, so as to divide the

[73v]

(a) September 4th Lat: 40°S.— Dig The sea contained an incredible number of these animals.— I am enabled to add some new & verify former facts.— Within the body, in same plane as the mouth, there is flattened tube or cavity, which I have called the stomach. now this itself contains a delicate vessel (best seen posteriorly), & which pretty clearly terminates in an anus of on one side the body, just at commencement of the tail.— Examining many specimens (V Pt 1 Fig 1.)

Prop I find both some of gut-shaped bags (FF) & included globules vary; also that size & quantity of globules in (D) varies.— The globules in F are always much larger than in D: when there are but few in D the circulation is languid, & the 2 points of greatest intensity were at the bases of gut-shaped bags or the point of returning.— When (D) is in this case, F is small.— but when globules in F were highly perfected, D was full of regularly circulating granules.— I have no doubt at the internal base of (FF) there is a communication with D, although the included matter is distinct.— When globules were large in FF, I perceived on the external base a conical pap (V Fig. n n), which even projected slightly beyond line of body.— It is probable that the ova are excluded through this when ready.— In this specimen globules were very easily detached.— XXX

74

1832 August

Polype? pulpy mass into three four columns. Within these I clearly saw a circulation somewhat like that (a) in the Chara: it was double the matter flowing upwards on the 2 outsides & then returning by the central divisions.— The circulation was strongest on the outside in the outer & inside of inner columns.— it was also much more rapid at the base of tail than at its extremity.— I frequ could see the grains turn round & pursue an opposite course at each extremity of tail. With 1/20 focal distance lens the matter (as nearly as I could judge) passed over 2 divisions of 1/500 micrometer in 5".— but about the tail in double the time.— at the 5" rate the progress is one inch in 20′..8". And the tail being .15 of inch long, any grain would pass perform whole [sketch] circuit in 6′..2".— this I daresay is accurate as the greater & lesser rates at base & end of tail would counterbalance each other.— I cannot even guess what what this is analogous to in other animals: as mentioned at Page (2) the granular matter is sometimes confined to small kidney shaped masses.— I could not clearly see that there was any communication with the intestinal tube; perhaps there was with the two gut-shaped bags at their inner edges crosses. L X

At extremity of tail a fan of ciliæ is visible almost with naked eye: but they appeared delicate transparent hairs, arranged very close in one plane.— they would seem to be locomotive organs

[74v]

(a) Sept 4th These ciliæ adhere laterally, so as almost to form membrane.— in same manner as happens in a birds feather.— The animal uses its tail in another manner; when placed in a basin, it adheres firmly to the smooth sides, so as to prevent the water washing its body away.—

XXX [in margin:] For particulars about ova resembling these V. 104

eggs (Note about kidney shaped)

I have formerly mentioned that in some specimens FF is almost evanescent.— From these facts showing connection in the two parts, I imagine that the ova (are first formed in D & then pass on into ?) F where they are perfected & then excluded or burst forth by the pap (n). If (D) had no connection with ova, why should the quantity & size of small globules or grains vary.— Again if it was a vascular [illeg] the communication with rest of body would be more evident.—

I watched one of the ova after being removed from ovary.— (never taking my eyes from it).— the process as described when went on till the ova appeared made up of two equal balls.— they then separated; a capsule remaining; the other composed of globular mass of pulpy-granular matter, in which was the a small transparent ball.— This is the real ovum & is the same which is seen in balls (L, O).— I had imagined that the whole of excluded mass consisted of granular matter.— The process of separation took about 10 minutes.— Before they parted a line of division appeared which gradually widened on each side.—

75

1832 August

Polype? (n) or rather to act on the water when the animal propels itself by starts.—

On each side of the intestinal tube is a gut shaped bag (F)4 filled with large grains, & if connected at all with the tail it is at the base by the side of intestinal tube.— The grains or globules are transparent, vary in length from 1/100 to 1/50 of inch, in shape are pointed oval & attached by the sharpest end in rows to the receptacle:— (L) represents a large one when first liberated, with high power a small internal ball may be seen not quite so transparent: (I saw following phenomenon take place in two good instances) in a few minutes (L) altered its shape & became like (O) with a small globule at its apex: in short time afterwards a greater change took place, the little globule (as in P) increased in size & the internal matter in both became opake & granular.— This went on till all the granular matter was expelled out of the larger into the smaller: the former being left an empty capsule, the latter separating as a small ball of granules.— After the change of transparent fluid into the granular mass, the expulsion (as represented at P) wore the appearance of an internal case or membrane contracting & thus expelling it into the globule.— I must suppose the gut-shaped bag to be ovaries.— & the granules eggs collected in capsules (L: O).—

The construction of the head is beautiful & simple, but not easily described.— When not in action

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(a) The smaller bristles only cross the others when the latter are clasped together. I did not perceive these, till I had a high power in microscope.

(b) the central bristles are longest: teeth would be a more appropriate term.

(e) Fig E badly represents the head or mouth in action, the arm (kk) partly expanded.—

(f) Sept 4th. The orifice of mouth is longitudinal, & situated on oblique surface formed by the back part of head.—

76

1832 August

Polype? the shape is a truncate cone (as before p. 2 described) & a transverse section of base would be an oval.— But when in action (mkk) is a transverse section of base; the dots are places (e) of bristles, seated on moveable arm or jaw kk.— These when closed in, form the oval.— The semicircular part (m) is continued upwards rather higher than the bristles when erect; near its summit are 2 rows of very minute bristle which project (a) out transversely; that is, cross the summit of the larger upright bristles.— The animal having seized any prey with the larger one, these smaller ones like a comb would effectually prevent its escape between their extremities.—

(F) The mouth is within (m).— The bristles (b) are 16 in number; 8 on each side, curved, slightly hooked at extremities & strong; besides the power of clamping together on the head, each bristle can separate itself from the next, so as to take in greater span.— When we consider this together with the power of motion in base (k), it makes a formidable instrument to seize any object, & when once within, the comb of small transverse bristles would effectually prevent its egress.— The substance of body is very sticky & gelatinous.— The range of Latitude is great of this animal: The more I understand of its organization, the more I am at a loss where to rank it amongst other animals.—

[76v]

(a) 347

(b) 348

(c) 354


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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

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