239 

 THE MARINE MOLLUSCA OF SAO THOME, I. 



By J. R. LE B. TOMLIN, M.A., and L. J. SHACKLEFORD. 



(Read before the Society, Sept. 9th, 1914). 



The material from which the following list has been compiled was 

 collected in S. Thome by Mr. J. Chalmers. He was unfortunately 

 unable, for various reasons, to do any dredging, and we gather that 

 the heavy surf would make dredging a very difficult operation in a 

 small boat. The list is, therefore, exclusively a record of shore col- 

 lecting. Mr. Chalmers also sent home large quantities of coarse 

 coral gravel from which all the small shells were sifted, but a very 

 large proportion of specimens from this source was too rolled and 

 worn for identification, otherwise our list \vould be considerably 

 larger. Even as it is we are able to make a considerable addition to 

 the authentic records from this island. 



The only list that has been published, so far as we are aware, is 

 Nobre's " Sur la Faune Malacologique de S. Thome," subsequently 

 incorporated (M. Nobre informs us) in his " Materiaux pour I'etude 

 de la Faune Malacologique des Possessions Portugaises de I'Afrique 

 Occidentale " (1909), published in the Bulletin de la Societe Portu- 

 gaise des Sciences Naturelles, tome iii., suppl. 2. In this paper 126 

 species are recorded for S. Thome, 57 of which have not occurred in 

 our material. The ensuing list records 188, making a total of 245 

 for the island. 



There are, however, probably a few misidentifications in M. Nobre's 

 list, which would slightly reduce this total. We record below 31 

 species which are common to the West Indies, as compared with 15 

 in Dautzenberg's " Contributions a la Faune Malac. de I'Afrique 

 Occidentale" in Actes de la Societe Linn, de Bordeaux, 1910 — a 

 paper in which the author ascribes the presence of West Indian 

 species on the West African coast to the branch of the Gulf Stream, 

 known as the Canaries current, which crosses the Atlantic from the 

 Gulf of Mexico to Portugal, and tlien runs southwards along the 

 African coast. We do not, however, recollect reading of the occur- 

 rence of any West Indian shells on the Portuguese coast. 



The marine mollusca of S. Thome obviously have a very close 

 affinity with those of the Cape Verdes, but though so much further 

 south — S. Thome lies practically on the equator — the tropical element 

 seems much smaller than in the Cape Verdes. Apart from a few 

 species of very wide distribution, the Cape element is almost absent. 



Our thanks are due to Mr. T. Iredale, M. Augusto Nobre, M. Ph. 

 Dautzenberg, and the Marchese di Monterosato for much kindly help. 



