164 68 



Several specimens of a shorter, and venlricose form (long. 18 mm., alt. 13 mm., 

 crass. 9 mm.) were taken at Koh Kahdal (in 1 — 5 fathoms, on a sandy and stony 

 bottom); a similar form was taken at Koh Mak (in 5—6 fathoms). 



Fam. Astartidae. 



Carditella pusilla, n. sp. 



(PI. Ill, Figs. 3-5). 



This species is rounded (with the exception of the somewhat prominent 

 beaks), a little inequilateral, dully pellucid, and whitish, (some specimens have 

 brownish-red spots and tints); fairly thick and convex valves, provided with a 

 broad, smooth, heart-shaped lunule, which is distinctly prominent along the middle. 

 The sculpture consists of 12 — 13 broad, rounded, radiating ribs, which are at least 

 3 times as broad as the interstices between them, and are covered with close-set, 

 fine, transverse tubercles. The umbones are acute, median in position, well in- 

 curved, and inclined over towards the front. There is a single central, strong, acute 

 triangular cardinal tooth in the right valve which fits in between two divergent 

 but smaller teeth in the left. The lateral teeth are distinct on both sides, the 

 anterior in the right valve and the posterior in the left being separated from the 

 outer margin by a deepish groove, the posterior in the former and the front one 

 in the latter being, on the contrary, on the margin. The hinge-plate between the 

 cardinal and the lateral teeth is seen under magnification to be finely transversely 

 striated. The interstices between the ribs, wherever they appear at the margin, 

 make the latter dentate, and these teeth are each provided on the inner side with 

 a small nodule. 



Long 25 mm., alt. 25 mm., crass. 2 mm. 



Between Koh Rin and Cliff Rock, 15 fathoms (Vs). Koh Kram, 30 fathoms 

 (2 + '"'s)- Koh Mesan, 15 fathoms, stones (2). Between Koh Mesan and Cape Liant, 

 5—9 fathoms, sand {■^l■^). Between Koh Mesan and Koh Chuen, 25-38 fathoms, 

 stones (1 + ^/s). Koh Chuen, 10—30 føthoms (''la). South of Koh Chuen, 30 fathoms, 

 shells ('/a). Koh Kahdat, 1 — 5 fathoms, sand and stones ('/s). 



This species is most nearly related to Carditella infans, Edg. Smith, and in 

 my diagnosis I have kept closely to Edg. Smith's description of that species, so that 

 by comparing the diagnoses it may be easier to form an idea of the differences 

 between the two species. In the British Museum there is a CarditeUa-îorm labelled 

 "Psepbis delecta, A. Ad. (Goiildia delecta)" which is closely related to my species, 

 but diflers from it specifically. 



Carditella pulchella, n. sp. 



(PI. Ill, Figs. «-8). 

 This little species is oval in form, whitish, often ornamented with brownish- 

 red spots which appear most distinctly on the interior of the valves; the shell is 



