92 rKOCEEDINGS OF TIIK MALACOLOGICAL SOCIETY. 



Callithaca, Dall, 1900. Type, Tapes tenerruna. Carpenter. 



Shell broadly obloiiii', sculptured, with tine radial riblets, crossed 

 by distant concentric ridges. Hinge-plate long with a space in front 

 of the teeth. Dorsal margins not grooved ; ventral margin feebly 

 crenulated when young, but smooth in adult. Pallial sinus very 

 long and turned up at the end. Pedal scar elongate, separate, with 

 a connecting canal. 



This species appears to stand by itself, and its dentition is very 

 different from that of Protothaca, with which Dr. Dall placed it. 



Genus Paeatapes, Stoliczka, 1871. 



Svuonyms : Pullastra^ Adams; Textrix, E-omer, 1857 (not of 

 Suudeval) ; Eutapes, Cliiaraenti, 1900; Piq)]da, Dall after Jiolten, 

 1902; Protapes, Dall, 1902. 



Shell smooth or concentricalh'' ribbed ; generally coloured with 

 a glistening brownish periostraciim. Lunule defined, but not the 

 escutcheon. Hinge-plate narrow, teeth short, near together, slightly 

 divergent, and of nearly equal length. Right dorsal margin grooved. 

 Pallial sinus moderate and rounded. Pedal scar always separate from 

 that of adductor. 



Paratapes, s.s. Type, Venus textilis, Liun. (= textus, Chem.). 



Shell oblong-elongate. Two of the teeth in each valve bifid or 

 grooved, and the posteriors curved. Pallial sinus obtuse and ascending. 



Tliis section includes u7idnlaUis, Born, rotundatus, Linn., sulcosus, 

 Sow., amabilis, Phil., semirugatus, Phil., jyolitus. Sow., grajfei, Dunker, 

 schneUiajius, Dunker, inJJatus, Desh., meroeformis, Sow., liratus, Phil., 

 eughjptus, Phil., malaharicus, Chem., and declivis, Sow. 



Po//^iYrtji'6s, Cliiaraenti, February, 1900. Type, Venus anrea^Gmti\m. 



Sj-nonym : Callistotapes, Sacco, April, 1900 (type, 2\xpes vettdus). 



Shell oval or oblong, concentrically grooved, with sometimes obscure 

 radial striation. Pallial sinus nearlj' horizontal. 



This is a small group of European and West African shells which 

 seems to take the ])lace of Paratapes in those regions. There are 

 a number of Mediterranean forms which some regard as varieties 

 of auretcs, but Icetus, Poli, texturatus, Lam. ( = petalma), and 

 C'lstrensis, Desh., seem good species. Other species are rhomboides, 

 Penn. (^ = virgineus, axictorum), British, and durus, Sow., from West 

 Africa. It has fossil representatives in the Miocene and Pliocene 

 deposits. 



Genus Vknehupis, Lamarck, 1818. 



Type, Venus irus, Linnajus. 



Shell oblong, often irregular from its nesting habit. Sculpture of 

 radial lines or riblets, crossed by concentric ridges or striae. Lunule 

 indefinite. Escutcheon not defined, or onlj' on left valve. Hinge- 

 plate verv short and narrow, excavated and curtailed posteriorly, so 

 that all the teelh are very short, near together, and nearly parallel 

 to one another. Two of tliem in each valve are bifid or grooved, 

 but the teeth are often irregular and malformed. Groove on the 

 posterior dorsal margin obsolete. Ventral margin smooth. Pedal 

 scar separate from adductor. 



