JUKKS-BEOWNE : SYNOPSIS OF THE VENERID^. 81 



Shell sculptured in regular concentric ridges, which do not rise 

 into erect himellse, and seUlom show any radial striation. Inter- 

 spaces finely concentrically striated. Nymphs with one or two 

 longitudinal stripe. 



The majority of the species belonging to tliis section occur in the 

 Indian, Australian, and Pacific regions. They include tiara, Dillw., 

 foliacea, Phil., rohorata, Hanley, tsahelUna, Phil., berryi, Gray, and 

 roseotincta, Sow. In Europe it dates back to the Hehetian stage 

 of the Miocene ( V. dertnparva^} 



LiropJiora, Conrad, 1864. Type, Vemis athleta, Conmd. 



Shell sculptured in thick concentric ridges, which are rounded in 

 the centre, but pass into erect lanielloe posteriorly, and often show 

 radial striae on their ventral sides. The interspaces are concentrically 

 sti'iated. jS^ymphs more or less rugose. 



This group is chiefly American, and includes V. paphia, Linn., 

 V. marice, d'Orb., V. peruviana, Sow., and V. Icellettii, Hinds. In 

 Florida it appears to date back to the Oligocene, and there are many 

 Miocene species. 



Chamelea,^l.'6vQ\\, 1853. Type, Venus gallina,\Ann.. 



Synonyms: Ortygia, Brown, 1827 (not of Boie, 1826); Herynione, 

 Leach, 1852 (not of Blainville, 1828); Chamelm, Adams, 1857. 



Shell sculptured in narrow close-set concentric rounded riblets, 

 which are often obliij^ue and irregular ; the radial striae are sometimes 

 faintly visible. Kymphs nearly smooth. Pallial sinus angular. 



V. inter purpurea, Conrad, of the Caiibbean Sea, and V. crassa, 

 Q. & G., of New Zealand, may be referred to Chamelea, and the group 

 dates back to the Miocene epoch in Europe ( V. cotJmrniai, Dujardin), 

 and to the Oligocene in the United States. 



Salacia, Jukes-Browne, 1914. Type, Venus lameUata, Lam. 

 Etym. : Salacia, the wife of Xeptune. 



Shell oblong or oval, flattened at the umbones, with distant, thin, 

 erect, or recurved concentric lamellae. Lunule small and lanceolate. 

 Escutcheon only defined in left valve. Median teeth always bifid. 

 Nymphs smooth. Margins feebly cienulate. Pallial sinus moderately 

 deep. Pedal scar long, narrowly confluent with adductor. 



This group seems to be restricted to Australia and New Zealand. 

 It comprises Chione yatesi. Gray, and Ch. jacksoni, Smith, and perhaps 

 C. calophylla, whicli links it with Cla^isinella. 



Bassina, J. -Br., 1914. Type, Venus paiicilaniellata. Sow. (= V.alata, 

 Reeve). Dedicated to Lieut. Bass, after whom Bass' Straits were 

 named. 



Shell sub-trigonal, thick, convex, brownish, concentrically striated 

 \>ith only a few erect scales on the anterior slope. Escutcheon not 

 defined. Both dorsal margins of the right valve grooved, and those 

 of the left bevelled to fit. 



The only species known occurs along the south coast of Australia 

 and round Tasmania. 



^ It was by mistake that this species was referred to Circomjyhalus on p. 74. 



