SOUTH AFRICAN MARINE MOLLUSKS. 211 



which are closely spaced at the anterior end, becoming gradually 

 more diffused posterior to the umbones. The junction of the radiat- 

 ing riblets with the lamellae, form slender cusps. Dorsal callus 

 thick, strong, and decidedly reflected. 



The type and two valves of this species (Cat. No. 186965, U.S.N.M., 

 come from Port Alfred (Coll. No. 337). The type measures: Length, 

 41 mm.; altitude, 12 mm. Another specimen, Cat. No. 187177, 

 U.S.N.M., comes from the same place (Coll. No. 728). This speci- 

 men is much stouter than the other, measuring: Length, 35 mm.; 

 altitude, 17 mm. 



This is the species which has been listed from South Africa as Pholas 

 fragilis Sowerby, which is a Philippine shell coming from Bassy, 

 Samar Island. I have material from the type-locality and find that 

 this species differs from the present in being much thinner and much 

 more strongly and distinctly sculptured, and altogether more elegant. 



BIBLIOGRAPHY. 



In this bibliography only such works have been cited as are absolutely necessary 

 to an understanding of the nomenclature of the South African mollusks. 



Abraham, P. S. 



1877. Revision of the Anthobranchiate Nudibranchiate Mollusca, with descrip- 

 tions or notices of forty-one hitherto undescribed species. Proc. Zool. 

 Soc. of London, pp. 196-269. 

 Adams, Arthur. 



1850. An arrangement of Stomatellidae, including the characters of a new genus, 



and of several new species. Proc. Zool. Soc, London, pp. 29-40. 

 1850. Monographs of Cyclostrema, Marryatt, and Separatista, Gray; two genera 

 of gasteropodous mollusks. Proc. Zool. Soc, London, pp. 41-45. 



1850. A monograph of Phos, a genus of gasteropodous mollusca. Proc. Zool. Soc, 



London, pp. 152-155. 



1851. Catalogue of the species of Nassa, a genus of Gasteropodous Mollusca belong- 



ing to the family Buccinidae, in the collection of Hugh Cuming, Esq., 



with the description of some new species. Proc. Zool. Soc, London, 



pp. 94-114. 

 1851. Descriptions of fifty-two new species of the genus Mitra, from the Cumingian 



Collection. Proc. Zool. Soc, London, pp. 132-141. 

 1851. On the animal of Liotia; with descriptions of new species of Delphinula 



and Liotia from the Cumingian collection. Ann. Mag. Nat. Hist., ser. 



2, vol. 7, pp. 332-333. 

 1854. Descriptions of thirty-nine new species of shells, from the collection of 



Hugh Cuming, Esq. Proc. Zool. Soc, London, pp. 130-138. 

 1854. Descriptions of twenty-seven new species of shells from the collection of 



Hugh Cuming, Esq. Proc. Zool. Soc, London, pp. 311-317. 

 Adams, Arthur and Reeve, Lovell. 



1850. The zoology of the voyage of H. M. S. Samarang. Mollusca, pp. i-x, 1-87. 

 Adams, Henry. 



1860. Description of a new genus and species of mollusk. Proc Zool. Soc, 



London, pp. 450-451. 

 Anton, H. E. 



1839. Verzeichniss der Conchylien, pp. i-xvi, 1-110. 



