148 52 
The Gulf of Klong Salakpat (south end of Koh Chang); many specimens; 
occurred in large lumps, attached to each other by their byssus-threads. 
As the relation between the height and the breadth varies greally in the 
different 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 (DavuTzeENBERG), Australia (REEVE), Port Curtis 
(“Alert”). “P. ephippium L.” has been recorded from the following localities:— Singa- 
pore, Mergui Archip., Nicobars, Mozambique and Madagascar, Mauritius. — Celebes, 
Philippines, Sorong (TAppARONE CANEFRI), Port Curtis (East Australia), West Australia. 
The West-Indian species P. alata, Gmel., bears much resemblance to P. Cumingi, 
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. ephippium L., if these two species are maintained? 
Perna nucleus, Lam. 
Perna 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., VII, 1 Abth., p. 36, pl. 13, fig. 1. 
Melina _— Lamarck, Lamy, Bull. Mus. d’Hist. Nat. Paris, 1906, p. 314, No. 70. 
Perna pectinala, Reeve, Conchol. icon., XI, Perna, Sp. 2. 
—  quadrangularis, REEVE, loc. cit., Sp. 6. 
Koh 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 Isls., Fiji Isls., New Holland (LAmMARcK). 
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, Schum., P. lobata, Reeve, P. 
spathulata, Reeve, P. dentifera, Krauss. 
Pinna inflata, Chemn. 
Pinna inflata, Curmnirz, Conchyl. Gabin., VII, 1785, p. 215, pl. 87, fig. 771. 
— — — Reeve, Conchol. icon., XI, Pinna, Sp. 5. 
- = Martini u. CHEemnitrz, Conchyl. Cabin., VII, 1 Abth., p. 80, pl. 34, fig. 1. 
W. of Koh Chang, 20 fathoms, mud (1). 
Long. 136 mm., alt. 82 mm. 
Distribution: — Nicobars, Ceyion. — Philippines. 
Pinna hystrix, Hanl. 
Pinna hystrix, HANEY, Proc. Zool. Soc. London, XXVI, 1858, p. 226. 
— — Reeve, Conchol. icon., XI, Pinna, figs. 60—61 (and the register). 
' Annals and Magaz. of Nat. Hist, 5 Ser., vol. 17, 1886, p. 138. 
