81 igh 
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 byssus 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 upper 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 valye; this valve has moreover two diverging cardinal teeth 
separated by a triangular space in which the ligament is located. 
Long. 45 mm., alt. 2°75 mm., crass. 2°55 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 Kellya 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 Kellya-forms). Sroriczka? puts Kellya = Erycina. P. Fiscuer® 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-méme servir, a 
premiere vue, a distinguer les deux genres: les Erycina sont orbiculaires et, quand 
elles ne sont pas équilatérales, c’est le coté antérieur qui est le plus long; au con- 
traire, les Kellia sont plutot subtriangulaires ou obrondes et le coté 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 Erycina-species described by CossMann (loc. cit.) come, also 
in regard to the main characters, very near to K. lineata. 
Kellya cycladiformis, Desh. 
Erycina Cycladiformis, Desuayes, Traité élément. de Conchyliologie (1839—53), pl. 11, figs. 6—9. 
— =_ — Proc. Zool. Soc. London, XXIII, 1855, p. 181, No. 2. 
Kellia cycladiformis, Hurron, Manual of the New Zealand Moll., 1880, p. 157. 
1 Die Conchylien d. Mittelmeeres, I, 1867, p. 180. 
* Paleontologia Indica. Cretaceous fauna of the Southern India, III. The Pelecypoda, 1871, p. 263. 
5’ Manuel de Conchyliologie, 1887, p. 1025. 
* Annales de la Soc. roy. Malacolog. de Belgique, XXII, 1887, p. 61. 
D. K. D. Vidensk. Selsk. Skr., 7. Reekke, naturvidensk. og mathem. Afd. V. 3. 93 
