MALACOZOA. TROPIOPODA. LAMELLIBRANCHIATA. 215 



and a depression in the other. Named after Mr. 

 O'Kelly, of Dublin. Turton. 



1 . Kellia suborbiculdris. Shell roundish-elliptical, 

 isomeral, convex, very thin, fragile, semitransparent, 

 obsoletely concentrically striate. Suborbiculdris, nearly 

 spherical. 



2. Kellia r ubra. Shell ovato-rotundate, anisomeral, 

 convex, moderately thick, obsoletely concentrically stri- 

 ato-sulcate. Ruber, red. 



GENUS 2. LEPTON. Shell suborbicular, equivalve, 

 compressed, slightly open at the ends, concentrically 

 striate ; umbones small ; hinge with a small tooth and 

 two depressions in one valve, a medial depression and 

 two lamelliform lateral teeth in the other. AOTTOS, thin, 

 small. Turton. 



1 . Lepton nitidum. Shell ovato-orbicular, subtrigonal, 

 nearly equilateral, semitransparent, glossy, faintly striated 

 concentrically. Nitidus, shining. 



GENUS 3. CRYPTODON. Shell suborbicular, nearly equi- 

 valve, inequilateral, concentrically striate ; umbones 

 small ; hinge with a small tooth in each valve, and 

 thickened margins ; two longitudinal plicae along the 

 posterior margin. Kpytrrbs, concealed ; odovs, tooth. 

 Turton. 



1. Cryptodon flexutisus. Shell suborbicular, very 

 convex, thin, brittle, transparent, with a deep sinus 

 bounded by two rounded plicae on the hind part of each 

 valve. Flexu6sus, bent or winding. 



GENUS 4. TELLINA. Shell roundish, subtrigonal, or 

 oblong, inequivalve, inequilateral, concentrically striated, 

 much compressed, umbones small, hinge with two small 

 teeth in each valve, or two in one, and a single tooth in 

 the other ; ligament external and prominent. Name 

 obscure. Linnaeus. 



1 . Tellma solidula. Shell orbiculato-trigonal, convex, 

 obsoletely rugoso-striate, varying in colour from white to 

 pink. Solidulus, small and firm. 



2. Tellma crfosa. Shell ovato-orbicular, compressed, 



