13 109 
Placuna sella, GMELIN, Encyclop. méthod., pl. 174, figs. 1 et 3—4. 
-- — — Martini u. Cuemnirz; Conchyl. Cabin., Vil, 1. Abth., p. 64, pl. 5, fig. 1. 
— — — Reeve, Conchol. icon., XVIII, Placuna, Sp. 1. 
— — -- P. FiscHer, Catal. d. Moll. de l’'Indo-Chine, p. 208. 
Placenta Ephippium, Rerzius, Diss. sist. noya testaceor. genera, 1788, p. 16. 
“Les greves du golfe de Siam” (Mortert).! 
The Danish Expedition to Siam collected no specimens of this species. 
Distribution: — Singapore, Mergui Archip. — Philippines, China, Java, Blitong 
(post-tertiary), Celebes, Amboina, Obi Isls., Pelew Isls. 
Fam. Arcidae. 
Arca navicularis, Brug. 
Arca navicularis, BruGuIERE, Encyclop. méthod. Hist. natur. d. vers. 1, 1792, p. 99, No. 4. 
— - _— REEVE, Conchol. icon., Il, Arca, Sp. 70. 
— Epa. Smiru, Rep. Challenger. Lamellibranchiata, p. 259. 
— ~- Koper in Martini u. CHEMNitz, Conchyl. Cabin., VII, 2 Abth., p. 51, pl. 4, 
fig. 7, pl. 14, figs. 6—7. 
- - Moret, Journ. de Conchyl., vol. 37, 1889, p. 162. 
— — E. Lamy, Bulletin du Mus. d’Hist. Nat., Paris, 1904, p. 270. 
- — - Prircuarpd and Gar.irr, Proceed. Roy. Soc. Victoria, vol. 17, 1, 1904, p. 240. 
— — E. Lamy, Journ de Conchyl., vol. 55, 1907, p. 20. 
subquadrangula, Dunker, Philippi, Abbild. u. Beschreib. neuer od. wenig gekannt. Conchyl., 1847, 
Il, p. 210. (Arca 10), No. 3, Arca, pl. III, fig. 3. 
— = -- KoseLt in Martini u. CHemnirz, Conchyl. Cabin., VIII, 2 Abth., p. 67, 
pl. 19, figs. 5— 6. 
fusco marginata, = Novitat. Conchol., 1858—70, p. 1386, No. 157, pl. 45, figs. 12—14. 
= — = Kope_r in Marrint u. Cuemnirz, Conchyl. Cabin, VIN, 2 Abth., p. 69, 
pl. 20, figs. 1—2. 
var. linter, Jonas. 
Arca linter, Jonas, Zeitschr. f. Malakozool., 1845, p. 172. 
— — Puiviprt, Abbild. u. Beschreib. etc., H, p. 209, No. 1, pl. 3, fig. 1. 
— — = Kope_t in Marini u. Coemnirz, Conchyl. Cabin., VIII, 2 Abth., p. 19, pl. 6, figs. 1—2. 
— — — E. Lamy, Journ. de Conchyl., vol. 55, 1907, p. 20. 
— navicularis, BruG., Puitipri, Abbild. u. Beschreib. etc., I], p. 210, No. 2, pl. 3, fig. 2. 
— _— —  var., DunkKER, Index moll. mar. Japon., p. 232, pl. 14, figs. 16—17. 
Very common, many specimens taken between Koh Rin and Koh Kut, 4—38 
fathoms, shells, stones, mud and sand. 
Islands in the Gulf of Siam (L. Mor.et). 
Long. 2—59 mm. 
Distribution: — Gulf of Manaar, Aden, Suez, Madagascar (VorLtTzkow, Lamy), 
Durban (EpG. Smira). — Poulo Condor, Cochin China, China, Japan, Amboina, 
Blitong (post-tertiary), Torres Strait, North, East and South Australia, Tahiti, Salo- 
mon Isls., New Caledonia. 
' Journal de Conchyliologie, 1889, vol. 37, p. 161. 
