81 177 



prolonged, rounded. The valves are compressed in the middle, which makes the 

 ventral side concave; in this concavity there occurs between the valves an oblong 

 aperture through which the bj'ssus protrudes. The surface is entirely covered with 

 close-set, uniform, parallel, concentric, raised, longitudinal folds. The interior of 

 the valves is glossy; the right valve has two triangular, prominent cardinal teeth, 

 one on each side under the apex; there is just below the apex a small obtuse tooth 

 in close proximity to the anterior tooth ; on each side is a long lateral tooth, 

 parallel with the ujiper margin and separated from it by a groove; these grooves 

 receive corresponding long, lateral teeth which are situated directly upon the upper 

 margin of the left valve; this valve has moreover two diverging cardinal teeth 

 separated by a triangular space in which the ligament is located. 



Long. 4'5 mm., alt. 275 mm., crass. 25 mm. 



Koh Kram, 30 fathoms (1). S. of Koh Samit, 20 fathoms, mud (2). Off Tung 

 Kaben, 6 fathoms, mud mixed with sand (3). Between Koh Chuen and Koh Chang, 

 15 fathoms, mud (1). Between Koh Kahdat and Koh Kut, 6 — 10 fathoms, clay 

 mixed with sand, and shells (4). E. of Koh Mak, 20 fathoms, mud (1). 



Singapore, 2 — 3 fathoms (1). 



I shall not enter more closely, in this place, into the question how far the 

 genera Kellga and Erycina should be kept distinct, but it appears to me that the 

 characters given by several authors as distinguishing characteristics are not especially 

 valid. Weinkruff' even advises to retain the name Kellya for the recent and 

 Erycina for the fossil forms (though, as is well-known, there are not a few fossil 

 typical A'e//(/a-forms). Stoliczka'^ puts Kellya = Erycina. P. Fischkr ' refers only 

 the fossil forms to Erycina. Cossmann ' says regarding the genus Kellya in connec- 

 tion with Erycina: "La forme générale de la coquille peut elle-même servir, à 

 première vue, à distinguer les deux genres: les Erycina sont orbiculaires et, quand 

 elles ne sont pas cquilatérales, c'est le côté antérieur qui est le plus long; au con- 

 traire, les Kellia sont plutôt subtriangulaires ou obrondes et le côté antérieur est 

 généralement le plus court." According to this, my species Kellya lineata should 

 be referred to Erycina; the dental formula also closely resembles that of the latter 

 genus and several of the Eryc/na-species described by Cossmann (loc. cit.) come, also 

 in regard to the main characters, very near to K. lineata. 



Kellya cycladiformis, Desh. 



Erycina Cycladiformis, Deshayes, Traité élément, de Conchylioloyie i'1839— 53), pi. 11, figs. G— il. 



— - — Proc. Zool. Soc. Londuu, XXIII, 1855, p. 181, No. 2. 



Kellia cycladiformis, — Hutton, Manual of the New Zealand Moll., 188U, p. 157. 



' Die Conchylien d. Mittelmeeres, 1, 1867, p. 180. 



- Palæontologia Indiea. Cretaceous fauna of tlie Southern India, III. The Pelecypoda, 1871, p. 263. 



^ Manuel de Conchyliologie, 1887, p. 1025. 



* Annales de la Soc. roy. Malacolog. de Belgique, XXII, 1887, p. 61. 



I). K. n. Vi.lonsU. Sclsk. Skr., 7. Række, n.iturvi.lensk. oC matlieni, AW. V. 3. 23 



