898 PELECYPODA. [EulameUibranchia. 



Genus 1. CRASSATELLITES, Kriiger, 1826. 



Crassalellites, Kriiger, Arch, neuest. Entdeck. Urvvelt, ii, 1826, 466. Type : 

 C. sinuatus, Kruger. Crassatdla, Lamarck, 1801 ; not of 1799. Pachy- 

 thcerus, Conrad, 1809. Scambula, Conrad, 1869. Crassitina, Weinkauff. 

 1881. 



Shell equivalve, solid, oblong-oval or subtrigonal, attenuated 

 behind, close ; margins of valves smooth or crenate ; beaks small, 

 contiguous ; lunule distinct ; ligament internal, attached to the 

 resilifer ; hinge-plate heavy ; right valve with 1 anterior lateral tooth, 

 1 anterior cardinal tooth, 1 median strong cardinal, behind this the 

 resilifer, and below it 1 rudimentary posterior cardinal tooth, and 1 

 very slender posterior lateral tooth ; left valve with 1 anterior lateral 

 tooth, 2 cardinal teeth, of which the anterior one is stronger, followed 

 by the resilifer, below which there is a minute socket for the corre- 

 sponding rudimentary cardinal of the opposite valve, and 1 long and 

 strong posterior lateral tooth. Adductor- scars deep, rounded ; anterior 

 retractor-scar of the foot small, distinct, not confluent, situate above 

 the anterior adductor-scar. Pallial line simple. 



Distribution. Australasia, Philippines, west coast of Africa, 

 Canaries, Brazil. 



Fossil. Cretaceous, Eocene, and Miocene. 



KEY TO SPECIES. 



A. Shell slightly produced and rounded posteriorly ; lunule narrow 



and long . . . . . . . . . . . . bellulus. 



B. Shell angled and truncated posteriorly ; lunule shorter, lanceolate obesus. 



1. Crassatellites bellulus, A. Adams, 1854. Plate 58, fig. 14. 



Crassalella bellula, A. Adams, P.Z.S., 1852 (1854), 95 ; M.N.Z.M., 158 : 

 Hutton, P.L.S. N.S.W., ix, 526. Gouldia Isabella, Hutton, C.M.M., 

 1873, 76. 



Shell ovato-trigonal, subequilateral, yellow, concentrically plicated. 

 Beaks sharply pointed, contiguous, the prodissoconch forming a minute 

 cone with concentric striation, crowned by a convex cap. Anterior 

 end shorter, regularly convex, the dorsal margin descending, straight ; 

 posterior end slightly produced and attenuated, narrowly rounded, the 

 dorsal margin straight, descending ; basal margin slightly rounded. 

 Lunule distinct, deep, narrow, and elongate. Escutcheon narrow, exca- 

 vated. Sculpture consisting of concentric strong wavy folds, which 

 are rather crowded and are getting smaller and obsolete at the anterior 

 and posterior ends. Epidermis thin, not shining. Colour uniformly 

 yellowish-pink. Interior yellowish-white, porcellanous. Margins finely 

 crenate. Hinge with the anterior cardinal tooth very slender. Resilifer 

 elongately ovate, vertical. Adductor-scars subequal in size, the anterior 

 more oval. 



Length. 21 mm. ; height, 15 mm. ; diameter, 9 mm. 



Type in the British Museum. 



