150 54 



East of Koh Chuen, 9—10 fathoms, shells (2). 

 Long. 30 mm. 



Distribution:— Aden (Edg. Smith), Durban (Sowerby). — Moreton Bay, 

 Queensland (Reeve). 



Note. In PI. II, Figs. 19 — 20, I have given figures of a young specimen oî Pinna 

 sp. (taken between Koh Kut and Koh Kahdat, in 10 fathoms; 18 mm. long) with 

 a very well-])reserved prodissoconch, which is distinctly separated from, and highly 

 different from the later increment to the valve. (R.T.Jackson says in "Phylogeny 

 of the Pelecypoda," Boston 1890, p. 332, when mentioning the group Perna, Avicula, 

 and their near allies: "The genera Malleus and Pinna might be considered in this 

 section, but I have not succeeded in getting very young specimens of either genus," 

 and later on, p. 385, "I have not had opportunity to study the Pinnidce satisfactorily 

 as attempts to obtain very young specimens have so far failed ;" in the specimen 

 of a young Pinna sp. figured in his Fig. 53 the prodissoconch is also wanting). 

 Pelseneer,' in his "System," places the genus Pinna under the order Eulamelli- 

 branchia, near to Ostrea and Lima, while Avicula (Pteria) is found under the 

 order Filibranchia. F. Bernard,- who has later examined the development of the 

 shell of the gen. Pinna, has reached another opinion, though the material at his 

 disposal, as he says, has been very small. The result of his researches is, that the 

 gen. Pinna belongs to Mytilidae. The scanty material at my disposal prevents me 

 from entering more fully into the question. 



Fam. Spondylidae. 



Spondylus Sinensis, Sow. 



Spondijlus Sinensis, Sowerby, Thesaurus Conchylioruin, 1. 1847, p. 427, pi. 87, figs. 32— 34. 



— — — Keeve, Conchol. icon., IX, 185(1, Sjiondylus, Sp. 7. 



S. of Koh Chuen, 30 fathoms, shells (1). West coast of Koh Chang, 10 fathoms, 

 mud (1 4" ^/ä). Between Koh Chuen and Koh Chang, 15 fathoms, mud ('/a). E. of 

 Koh Mak, 20 fathoms, mud (1). Between Koh Kut and Koh Kahdat, 10 fathoms, 

 shells (1 + V-'). S. of Koh Kahdat, 8—10 fathoms, mud (1). W. of Koh Kut, 15 

 fathoms, mud (2). 



Long. 3 mm., alt. 35 mm. 

 — 46 mm., — 56 mm. 



Distribution: — Poulo Condor, Cochin China, Annam, China, Japan. 



The valves are quite white in one of the specimens from the Gulf of Siam.-' 



Spondylus coccineus, Lam. (Reeve). 



Spondylus coccineus, Lamabck, Hist. nat. d. anim. s. vert., VI, 1 part., 1819, p. 190, No. 11. — éd. 2, VII, 1836, 



p. 188, No. 11. 



— — — Reeve, Conchol. icon., IX, Spondylus, 185(>, Sp. 44. 



— ocellatus. Reeve, Conchol. icon., IX., Spondylus, Sp. 4;!. 



^ A Treatise on Zoology, ed. by E. Ray Lankester, V, Mollusca by P. Pelseneer, London 1906, p. 263. 

 - Recherches ontogén. et morphol. sur la coquille d. Lamellibranches. Annales d. se. natur. Zoologie, 

 VIII, Paris 1898, pp. 45 et 85-86. 



^ Comp. Dunker, Index moll. mar. Japon., 1882, p. 245. 



