47 143 



Commonly distributed between Koh Rin and Koh Kong. 1 30 fathoms, mud, 

 sand, gravel, shells and stones. The specimens gathered were almost all young 

 individuals. 



Long. 10—38 mm., alt. 10—32 mm. 



Distribution: — Malacca, Singapore, Madras, Ceylon, Palk's Strait, Gulf of 

 Manaar, ' Maldives, Persian Gulf, Gulf of Aden, Red Sea, Suez (since the opening of 

 the Suez Canal this species has wandered into the Mediterranean. There are typical 

 examples from Alexandria and Malta in the British Museum.-), Mauritius, Bazaruto 

 Isl., Durban. — Philippines, Japan ('?), Flores, Sandwich Isis., Torres Strait, North 

 Australia, East Australia (as far as Sydney), West Australia (as far as Sharks Bay), 

 New Guinea, New Zealand (Gould). 



I have followed H. L. Jameson (1. c.) in his opinion regarding P. vulgaris, 

 Schum., although I feel convinced that several of the species in his "Section c" are 

 nothing else but varieties of this species. Schumacher's original specimen is in 

 the Zoological Museum of the University of Copenhagen, and I can only confirm 

 Jameson's opinion that P. vulgaris, Schum., is identical with P. fucaia, Gould. 

 P. vulgaris, Schum., has had numerous names given to it, owing to its variability 

 in shape and colour. Thus A. H. Cooke ^ enumerates the following of Reeve's 

 species as identical (the original specimens in the 'British Museum" were at his 

 disposal): — imbricata, muricata, lentiginosa, occa, fimbriata, anomioides, aerata, 

 irradians, and nebulosa, Conr. Jameson (who has had the same specimens for 

 examination) gives: — occa, Reeve, aerata, Reeve, perviridis. Reeve, varia, Dunker, 

 and badia, Dunker, as synonyms of P. vulgaris, Schum. G. B. Sowerry^ believes 

 that Avicula flabellum. Reeve,'' and A. lacunata, Reeve, may be added to these. 

 A. Martensi, Dunker,'' is also, no doubt, nothing but a form of the present species. 

 G. F. Angas ' considers A. placunoides, Reeve, a variety of fimbriata, Reeve. 



' For details comp. L. G. Seurat, l'Huître perlière. Paris 19Ü1. — E. Im Thurn, Sketch of tlie 

 Ceylon Pearl Fishery of 1903. (Spolia Cej'lanica, I. Colombo 1U03). — J. Hohnei.i., The Biolog. Results 

 of the Cej'lon Pearl Fisherj' of 1!)Ü4. (Reports from the Ceylon Marine Biological Laboratory No. 1, 

 Colombo 190.'). — J. Caixott Gaskin (Proc. Zool. Soe. London, 190(i, p. 803), A Memorandum on the Pearl- 

 shells in the Persian Gulf. — Edg. Thursto.n, Notes on the Pearl and Chank Fisheries and Marine Fauna 

 of the Gulf of Manaar, Madras 1890. — Report on the Pearl Oyster Fisheries of the Gulf of Manaar, 

 by W. A. Heruman. 1— ö. London 1903 — 6. — P. vulgaris, Schum., is fished here on a large scale for 

 the sake of the pearls. 



- H. L. Jameson (1. c. p. 385) and Vassel, Sur la Pintadine du Golfe de Gabes (Comptes-rendus. 

 Assoc, franc, p. l'avancera, d. sc, 189(5, pp. 4ô8— (Ki). 



^ The Annals and Magaz. of Nat. Hist., vol. XVII, 1886, pp. 130—37. 



■* Appendix to Mai'ine shells of South Africa, Lond. 1897, p. 27. 



^ This is a form from Venezuela and A. H. Cooke says (1. c. p. 137| that the type in the British 

 Museum differs from A. fucata, Gould. 



* Index raolluscor. mar. Japon. Cassel 1882, p. 229, pi. 10, figs. 7—8. 



' Proc. Zool. Soc. London, 18(!7, p. 930. 



