TRIBE NYMPHACEA. 69 



same colour ; nymphse inflected ; within white with a tinge of 

 citron at each extremity : hinge with two cardinal teeth in each 

 valve and the lateral teeth approximate. 2 . . 2f . Young and more 

 oblong. — (Chloroleuca. Lam.) — European and Indian Seas. 

 T. LiNGUA-FELis. Liu. IIIQ.—D. p. 73. — Lam. 37.— E. t. 

 289./. 6.— Ch.f. 65.— Wood. G. C. t. 40. f. 2, 3.— JF. t. 3./. 2. 

 Roundish ovate, with the anterior extremity very obtuse ; roughened 

 by lunated scales disposed in quineunxes and rayed with pale pink 

 on a whitish ground ; beaks pink. 1 1 . . If* — India. 



T. RuGOSA. Born. t. 2. f. 3, 4. — D. p. 73.— Lam. 38.— 

 Wood. G. C. t.Al.f. 2, 3.—E. t. 290. f. \.— Ch.f. 62.— TF. t. 3. 

 f. 8. Roundish-ovate, anteriorly attenuated and inflected, with 

 transverse undulated membranaceous wrinkles, white tinged with 

 yellow at the beaks ; inside white ; hinge with a cleft and plain 

 tooth in one valve, and two plain with strong lateral ones in the 

 other. — New Holland. 



T. Lacunosa. Lam. 39.— Z>. p. 7&.— W. t. 3. f. 12.— 

 T. Papyracea. Gmel. 323\.—E. t. 290. f. \4.— Ch.f.78. 

 Roundish-ovate, rounded at one end and sub-truncated at the 

 other, whitish, thin, ventricose and transversely striated ; the 

 ventral margin depressed in the middle, with a sinuous twist. 

 Ij . . 24- — Guinea. 



T. Gargadia. Lin. \\16. — D.p. 72.—Ch.f. 63, 4.— Lam. 

 40. — W. t. 3. J'. 1. Roundish-ovate, compressed, cartilage slope 

 toothed, transversely and undulatingly wrinkled on the anterior 

 side and towards the ventral margin. H • . 1^. — Nicohar Isles. 



T. PuiSTis. Lam. 4\.—E. t. 287./. 1.— White, roundish-ovate, 

 anteriorly angulated and shorter, with sub-imbricated transverse, 

 and minute radiating strifie, the former becoming fine ridges on the 

 obliquely truncated anterior slope, whose depression is lanceolate 

 and concave, and its edge seemingly toothed ; hinge with a bifid 

 and lamellar tooth in each valve besides lateral ones. \h. — Indian 

 Ocean. 



T. PoLYGONA.— C/iem. /. 77. -D. p. 76— W. t. 3. /. 11.— 

 MuLTANGULA, Lam. 42. — Gmel. 3230. Ovate broadly tri- 

 angular, the anterior side the longer, sinuous, and almost biangu- 

 lated ; white with the beaks and margin yellowish, transversely 

 striated and somewhat decussated towards the margin : hinge with 

 a single cleft cardinal tooth in one valve and two in the other, no 

 lateral teeth. \\ . . 2\. — Tranqnebar. 



T. GuiNATCA.' Chem.f. 16.51, 2, 3.—D.p. 96.— T. Polygona. 

 Lam. A3.— Gmel. 3244.— Mont. t. 28./. 4.— TF. t.4.f. 80.? 

 Roundish-ovate, somewhat triangular, flexuous and sinuated at 

 the ventral margin, white with the beaks and interior tinged with 

 pale orange, transversely striated ; hinge with two large cardinal 

 teeth in one valve and a large triangular cleft one, with an approxi- 



