148 52 



The Gulf of Klong Salakpal (south end of Koh Chang); many specimens; 

 occurred in large kimps, attached to each other by their byssus-threads. 



As the relation between the height and the breadth varies greatly in the 

 difîerent individuals, I give here the measurements of 3 different specimens: long. 

 96 mm., alt. 75 mm. — long. 92 mm., alt. 105 mm. — long. 4 mm., alt. 5 mm. 



Distribution: — Annam (Dautzenberg), Australia (Reeve), Port Curtis 

 ("Alert"). "P. ephippium h." has been recorded from the following localities:— Singa- 

 pore, Mergui Archip., Nicobars, Mozambique and Madagascar, Mauritius. — Celebes, 

 Philippines, Sorong (Tappauone Canefri), Port Curtis (East Australia), West Australia. 



The West-Indian species P. a/a/a, Gmel., bears much resemblance to P. Citmingi, 

 Reeve; they may, however, be distinguished from each other by the radiating lines 

 in the latter species, which give the growth-margins a crenulated appearance. But 

 what is to become of P. ephippiuni L., if these two species are maintained? 



Perna nucleus, Lam. 



Pcina nucleus, Lamarck, Hist. nat. d. anim. s. vert., éd. 2, VII, 1836, p. 78, No. 10. 



— — — Reeve, Conchol. icon., XI, Perna, Sp. 4. 



— — Reeve, Martini u. Chemnitz, Conchyl. Cabin., VIII, 1 Abth., p. 36, pi. 13, fig. 1. 

 Melina — Lamarck, Lamv, Bull. Mus. d'Hist. Nat. Paris, 1906, p. 314, No. 70. 



Perna pectinata, Reeve, Conchol. icon., XI, Perna, Sp. 2. 



— quadrangularis, Reeve, Ioc. cit., Sp. 6. 



Koli Lom, W. of Koh Chang (many specimens). 



1) Long. 10 mm., alt. 14 mm. 2) Long, et alt. 9 mm. 3) Long. 7 mm., alt. 

 9 mm. 



Distribution:— Mergui Archip., Red Sea, Suez, (Natal and Bourbon, P.dentifera, 

 Krauss). — Poulo Condor, Philippines, Samoa Isis., Fiji Isis., New Holland (Lamarck). 



This species is highly variable, as are all the forms belonging to this group. 

 A. H. Cooke has enumerated the following species, which he believes to be identical 

 with the present one: — P. nana, Gould, P. rostrata, Schuni., P. lobata, Reeve, P. 

 spathulata, Reeve, P. dentifera, Krauss. 



Pinna inflata, Chemn. 



Pinna inflata, Chemnitz, Conchyl. Cabin., Vlll, 1785, p. 215, pi. 87, lig. 771. 



— — — Reeve, Conchol. icon., XI, Pinna, Sj). 5. 



— — — Martini u. Chemnitz, Conchyl. Cabin., VIII, 1 Abth., p. SO, pi. ,i4, tig. 1. 



W. of Koh Chang, 20 fathoms, mud (1). 



Long. 136 mm., alt. 82 mm. 



Distribution:— Nicobars, Ceylon. — Philippines. 



Pinna hystrix, Hani. 



Pinna lujslrix, Hani.ey, Proc. Zool. Soc. London, XXVI, 1858, p. 226. 



— — — Reeve, Conchol icon., XI, Pinna, iigs. 60 — 61 (and the register). 



' Annals and Magaz. of Nat. Hist, 5 Ser., vol. 17, 1886, p. 138. 



