[1]

My Dear Sir

On the other leaf I have copied your list and stated what I believe will be found correct relative to each genus. My conclusion would be that the fossil shells of Navedad have not a particularly tropical character. The Cassis is small—a larger species is found in the Medn. though the large sorts are tropical. It may be doubted if Sigaretus be really found in the Medn. it is probable that it may belong to S. Australia. Perna abounds in tropical latitudes -and if any are found on the S. Australian coast - they are scarcely known - fossil species are found in Piedmont & Normandy &c. Harpa is one of the most decidedly tropical genera. Conus, Cypræa, Ovulum, Mitra, Terebra - Meleagrina, Perna, Voluta - Fusus -Triton &c may be regarded for the most part as tropical - though there are perhaps some exceptions in each genus. There is scarcely a genus of any extent that has not some species in temperate and extra-tropical zones. Thus there are Cones, Cowries, Mitres, Fusi, Tritons &c in the Medn:

Concerning Trigonocelia I believe there is not known any recent species: fossil species exist in our Europæan tertiary beds. How can D'Orbigny admit Trigonocelia if he turn out Cucullæa? Crassatella is not peculiarly characteristic of the Australian seas,

[2]

some species are found in the Atlantic and Indian seas. You know the recent Struthiolariæ belong to N. Zealand and the Trigonia abounds at or near to Sydney, N. S. Wales:

the genus is found fossil almost everywhere -

Thus have I, to the best of my abilities answered your queries - I hope satisfactorily and remain

My Dear Sir Your very obliged  G B Sowerby

 7th Feby. 1846—

Charles Darwin Esq.

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Gastridium.    I know no recent species; other fossil species are found "aux environs de Paris".

Monoceros,    the greater number belong to the Southern parts of S. America

Voluta,          ranges as you say to "Str. of Magellan" there are also some fine South

 Australian species (magnifica, fluctuata, Turneri, Zebra, pulchra &c) though

 I believe the greater number and those with most brilliant colours are tropical.

 Oliva            abounds in tropical latitudes; though some fine species are found to the

 northward: it can scarcely be regarded as in any degree characteristic of other

 than the tropics.

Pleurotoma    few species belong to temperate or Meditern. zones.

Fusus            ranges to high northern latitudes, though I believe the finer species are

                    intertropical.

Turritella         Your Navedad species might belong to temperate latitudes as far as they are

Trochus         concerned.

Cassis           in general tropical, some few small species are found north of the tropics -

                    there are also some S. Australian species.

 

Pyrula           tropical

Triton            some large species are found in M: Medn. & S. Australian.

Sigaretus       not entirely confined to tropical climates

Natica           has a most extensive range.

Bulla             also.

Terebra         though not entirely confined to tropical latitudes, is nevertheless very characteristic of them.

Dentalium      very nearly as Natica, though the large & fine species belong to the tropics.

Corbis           I believe tropical—as there is some uncertainty about your Navedad species, it would not be right to draw any conclusion from it.

Cardium        has a very extensive range.

Venus           do.

Pectunculus    do. its greatest developement in the Medn.

Cytherea       has a very extensive range.

Mactra          do.

Pecten          do.

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Note for Mr. Darwin relative to his addition to Struthiolaria ornata App. p. 12.

I see no objection to this addition being inserted, provided that the fact of Mr. Cuming having

found a living species of Struthiolaria at Arica be given on the authority of Mr. Cuming

himself and not on mine.

Mem: In my opinion the latin of Darwin is Darviniis—that of Sowerby— Soverbius—as w is

not a latin letter - Mr Darwin must use his own discretion.

I percieve Mr Darwin has altered the spelling of Navedad to Navidad - it is a subject with

which I am entirely unacquainted & only mention it for Mr Darwin's consideration.

Trigonocelia p. 4. The observation may properly stand as it is.