21 117 



Bijssoarrn piisilla, Sowkhhy, I'roc. Zool. Soc, I, 1833, p. 18. 



Area — — Reeve, C'.onchol. icon., II, Area, Sp. 112. 



— donticiformis, Heeve, Coiichol. icon., II, Area, Sp. 104. 



— (Byssoarca) pholadiformis, C. B. Adams, Shells coll. at Panama, 1852, p. 260. 

 ttarhalia [Acar) himinata, Angas, Proc. Zool. Soc, 1865, pp. 697 and 655. 



Area {Bijssoarca) dubia, Baird, Brenchlev, Jottinjjs during the cruise of H. M. S. (^uiaijoa among the 

 South Sea Islands. 1873, p. 453, pi. 42, figs. 5- 6. 



— M' CoYi, Tenison-Woods, Transact, and Proc. Roy. Soc. Victoria, vol. XIV, 1878, p. 61. 



Gulf of Slam ('/a). 



Long. 15 mm. 



Distribution: — Gulf of Manaar, Mangalore (Malabar Coast), Maldive Archip., 

 Arabian Sea, Gulf of Oman, Persian Gulf, Gulf of Aden, Red Sea, Gulf of Suez, 

 Mozambique, Natal coast, Seychelles, Amirantes, Madagascar, Mauritius, Cape of 

 Good Hope, St. Helena, Ascension, Annobon, St. Thome, Cape Verd Isis., Madeira. — 

 Tonkin, South Japan, Philippines, Moluccas, Torres Strait, North, East and South 

 Australia, Tasmania, the South Sea Islands, New Caledonia. — West coast of America 

 from St. Barbara to Peru; East coast of America: Bermudas, Florida, Gulf of Mexico, 

 Bahamas, Greater and Lesser Antilles. 



The wide distribution of this species, together with its great tendency to varia- 

 tion, has caused it to have numerous names given to it in the course of time. 

 LiscHKE, ^ and more recently Ed. Lamy, ^ have recorded a great many of these. 

 A. H. Cooke' doubts the correctness of Lischke's views upon the identity of these 

 species; he is of opinion that they are three well-distinguished forms: gradata (the 

 West American form), üomingensis -f squamosa (the West Indian form), divaricata, 

 Sow. = plicata, Ch. (the East Indian form); but the distinguishing characters 

 recorded by him are not valid. I have at my disposal a fairly large quantity of 

 material of il. Domingensis from the West Indies, and the extensive variation-series 

 includes, as far as I can see, all the forms which have been established. I think, 

 W. H. Dall is mistaken when he' reiers A. Domingensis, Lam., and gradata, Brod. & 

 Sow., from the Gulf of Mexico and the Caribbean Sea to A. reticulata, Ch. He sup- 

 poses that A. congenita, Edg. A. Smith, also, is possibly only a form oi A. plicata, Ch. 



Area (Acar) tenella, Reeve. 



(PI. 1, Figs. 11 — 13J. 



Area tenella. Reeve, Proc. Zool. Soc. London, XII, 1844, p. 124. 



— — — Conchol. icon., II, 1844, Area, Sp. 91. 



— (Barbalia) tenella, Reeve, Martini u. Chemnitz, Conchyl. Cabin., VIII, 2 Abtli., p. 155, pi. 39, tigs. 5—6. 

 Barbatia mollis. Dunker, Novitates concholog., 1867, p. 92, pi. 31, figs. 2 — 4. 



Area (Biirbatia) mollis, Dunker, Martini u. Chemnitz, Conchyl. Cabin., VIII, 2 Abth., p. 128, pi. 33, figs. 5 — 6. 



— {Acar) tenella. Reeve, Lamy, Journ. de Conchyl., vol. 55, 1907, p. 93. 



' Japanische Meeres-Conchylien, II, p, 142, III, p. 107. 



-' Journal dc Conchyliologie, vol.52, 1904, pp. 142— 47, and vol.55. 1907, pp. 80-87. 



^ Annals and Magazine of Nat. Hist., 5. Ser., vol.18, 1886, p. 94. 



* Report of the Mollusca of the "Blake' Expedition, I, 1886, p. 242. 



