150

March: East Falkland Islands

1833

Gasteropod for its whole length.— At the bottom of the cavity there is (I think) 3 rows of tapering, simple, white branchial fillets: on the right side within the cavity, there is (I think) anal orifice: Pænis very large, lying in the Branchial cavity, curved, flattened, & tapering.— seated behind the right antenna.— Foot oblong.— anterior margin truncate, scalloped or grooved with the corners recurved like horns: Head flattened, long, extensible, in front square, with antennæ on each side & eyes at the exterior base.— Mouth seated between the foot & head, longitudinally folded: Antennæ short, simple, cylindrical: Mantle covered with pointed papillæ: diameter .6: colour pale yellowish, with marks of flesh colour: in centre an irregular oblong mark of dark brown from which are sent off a reticulated vein work of same color:— Has power of considerable adhæsion to a smooth surface: can roll itself into a ball: was found at low water mark under a stone:—

(a) This animal would appear to belong to Pectinibrands; although most probably to Tectibrands:

Gasteropod 570 583 March 9th. Caught two specimens of same genus: but I think different species: Habitat &c same: Body rather more oblong: length one inch: colour dirty pale yellow, thickly clouded & veined with purplish brown: surface smooth with few small papillæ.— This seems the most specific difference:— Also another smaller; dirty yellow with dark brown dots, surrounded by a halo of light brown: Are these Species or Varieties?

[150v]

(a) It would appear to have an intimate relation with the family of Capubridis: thinking the Branchiæ are arranged in several rows is a more wide difference than the Shell being internal instead of external.

151

East Falkland Islands

1833 March

Doris March 9th. Under large stones, East Falkland Island.— Shape elongated oval; length 3 1/4 inches; breadth 1 & 1/2; flattened; mantle much projecting over foot & covering head & tail; colour uniform white, with a faint tinge of yellow; Surface, smooth to the touch, but thickly were studded with minute cylindrical papillæ.— This gives a fine fimbriated appearance to branchial orifice:— Branchiæ very large, frondescent, beautiful; primarily divided into eight divisions; each of these like a folded leaf.— divided into tufts, which are again subdivided: surrounding anus: Generative orifice large: Superior or dorsal antennæ, short, thick pointed, horn-shaped, faint brown colour, surrounded by concentric oblique membranous ridges, which are divided anteriorly by a white space: summit uncovered white: frontal antennæ small. I could not see the eyes:— but under (by dissection) mantle & behind the dorsal ones are two black dots resembling eyes: Digestive tube, gullet muscular, surrounded by (vermiform salivary glands?), entering between the Generative organs into centre of liver, is slightly enlarged & turns removed backwards, & reaches the anus in an oblique direction on the dorsal surface of liver.— Liver very soft, white & red:—

Eggs deposited in a ribbon. this adhæres by its edge to the rock in a spiral oval [sketch] of 4 or 5 turns. is evidently formed by the turning of the animal on its centre.— & the distance of axis is the length from generative aperture to centre of revolution in the foot: Eggs in diameter .003, are collected in number from 2 to 5, generally in a[n] oval transparent case or

[151v]

(a) Especially when it is recollected every individual is an Hermaphrodite & lays eggs:—

152

1833

Doris ball, length .012: These balls are arranged, two deep, in transverse rows in the ribbon:— In a large collection, the ribbon must be 20 inches long, in breadth it is .5 of inch; from counting how many balls in a tenth of inch & how many rows in same length, at the smallest computation there could not have been less than the enormous number of six hundred thousand eggs.— This is a wonderful instance of fecundity: yet the animal is certainly not common: I only saw seven individuals:—

Jan & Feb Tierra del Fuego (South of Lat 54°45')

General Observations Before mentioning any of the effects of climate, I will state, what I know, of its nature.— Capt King1 has observed during Autumnal & Brumal period.— & the thermometrical observations made in this ship include the hottest part of the year.

From the 18th of Decemb: to the 14th of Jan (a period of 18 days) the mean from 332 observations made meanly at every two hours interval gave

temp: 44.92

Mean daily Max: 47.98 Range

Min: 41.28} 6.7

Mean of extremes 44.63

During this time half was on the outer SE coast & half at sea, sometimes one or two degrees to the South of Cape Horn.—

From 15th of Jan to 20th of Feb (a period of 37 days) the mean from 161 observations, mostly at 6 AM: 12: 6 PM & some at the two hour interval give as:

Mean 49.9

Mean of Max: 55.54 Range

....... Min: 45.36} 10.18

Mean of extremes 50.45

During this time the Ship was in different harbors, in Nassau bay & in Goree Sound.