244 148 
Chione (Timoclea) imbricata, Sow. 
Venus imbricata, Sowersy, Thesaurus Conchyl., II, 1855, p. 715, pl. 156, figs. 81 —82. 
aa _ — Reeve, Conchol. icon., XIV, Venus, Sp. 118. 
Chione — _— ROmer, Malakozool. Blatter, XIV, 1867, p. 59, No. 46. 
Venus — _— Fiscuer, Catalogue d. Moll. de l’Indo-Chine, p. 273. 
— Cochinensis, — Thesaurus Conchyl., I, 1855, p. 716, pl. 156, figs. 79—80. 
Chione — — Romer, Malakozool. Blatter, XIV, 1867, p. 60, No. 47. 
“Gulf of Siam” (L. Mor.et). 
Distribution: — Mergui Archip., Ceylon, Red Sea(?). — Cochin China, 
China, Philippines. 
This species does not occur in the collections made by the Danish Expedition, 
Chione (Timoclea) scabra, Hanl. 
Venus scabra, HAnuey, Proc. Zool. Soc. London, XII, 1844, p.161. — Catal. of rec. biv. shells. Append., p., 
361, pl. 16, fig. 24. 
— — — Sowerby, Thesaurus Conchyl., II, 1855, p. 718, No. 45, pl. 157, figs. 101—2. 
Venus — — REEVE, Conchol. icon., XIV, Venus, Sp. 97. 
Chione — — RO6meErR, Malakozool. Blatter, XIV, 1867, p. 58. 
Venus (Chione) scabra, HANLEY, Epc. Smirn, Rep. on the Lamellibranchiata of the Challenger Exped., 
p. 124. 
DAUTZENBERG et FiscHER, Journ. de Conchyl., vol. 54, 1906, p. 217. 
Chione scabra, HANLEY, Metvitt & STANDEN, Proc. Zool]. Soc. London, 1906, p. 835. 
— micra, Pivspry, Proceed. Acad. Nat. Hist. Philadelphia, vol. 56, 1904, p.552, pl. 41, figs. 4—5. 
Very common; many specimens were taken everywhere between Koh si Chang 
and Koh Kong, in 3—20 fathoms, on a muddy and clayey bottom. 
Long. 2--16 mm. 
Distribution: — Poulo Penang (“Galathea” Exped.), Mergui Archip., Gulf of 
Manaar, Madras, Persian Gulf, Gulf of Oman. — Annam, Philippines, Japan, Mast 
Head Reef (Queensland). 
The present species varies considerably both in outline and in sculpture. Thus, 
Ch. micra, Pilsbry, is only a younger individual with fewer ribs; several specimens 
of similar forms (showing even transitional stages to the type-form) are at hand 
from the Gulf of Siam. 
Chione (Timoclea) Siamensis n. sp. 
(Pl. V, Figs. 6—7). 
This species is roundly trigonal, moderately convex, whitish, longer than high, 
and the posterior end is elongated and rather pointed. The umbo is situated in 
the anterior half of the valve and the ventral margin is siightly convex. The 
sculpture consists of strong, parallel, concentric ridges crossed by close-set radiating 
ridges, and at the points of contact rounded, bead-like granules are formed. These 
radiating ribs differ in thickness and are placed at different distances apart; thus 
at the anterior end there are 8—4 strong and prominent ribs, then follow, over the 
