Macrocallista.] PELECYPODA. 983 



margin of the valve ; the anterior lateral in the shape of a raised 

 tubercle. Ligament moderately strong, extending from the beaks to 

 the posterior end of the hinge-plate. Adductor-scars unequal, the 

 anterior oval, the posterior roundish. Pallial line distinct, distant 

 from the margin ; the pallia! sinus rather short and broad, free, angled 

 in front. 



Length, 34 mm. ; height, 24 mm. ; diameter, 17 mm. 



Type in the British Museum. 



Hab. Throughout New Zealand, in deep water : Bay of Islands ; 

 off Great Barrier Island, in 110 fathoms ; near Channel Island, Hau- 

 raki Gulf, in 25 fathoms ; Wellington (Captain Hutton) ; Queen Char- 

 lotte Sound, in 10 fathoms (" Challenger " Exp.) ; twenty-one miles 

 north-east of Wreck Reef, in 50 fathoms ; ten miles north-east of 

 Port Adventure, in 40 fathoms (E. R. Waite) ; Wet Jacket Arm,- 

 Dusky Sound, in 12 fathoms ; Port Pegasus, Stewart Island, in 

 18 fathoms (Captain Bollons) ; near Cuvier Island, in 38 fathoms 

 (Captain Bollons). 



Fossil in the Miocene and Pliocene. 



Genus 2. CYTHEREA, Bolten, 1798. 



Cytherea, Bolten, Mus. Bolten., 1798, 177. Types : Venus puerpera, L. ; 

 F. rugosa, Gmelin ; F. verrucosa, L. Gafrarium, Bolten, 1798 (in part). 

 Venusarius, Dumeril, 1806. Dosina, Gray, 1838 ; not Dosinia, Scopoli, 

 1777. Clausina, Brown, 1827. Omphalocla thrum, Morch, 1853. Venus, 

 Swainson, 1840 ; not of Linne and Lamarck. Calista, Leach, 1852 ; 

 not Callista, Morch, 1853. Callista, Fischer, 1887. Ventricola, Romer, 

 1867. Antigona, Romer, 1857. Artena, Conrad, 1870. Cytherea, Bolten : 

 Dall, Proc. U.S. Nat. Mus., xxvi, 1902, 354; Trans. Wagn. Free Inst,, iii. 

 pt. 6, 1903, 1271. Type : Venus puerpera, L. 



Shell large and rotund, valves convex, with strong sculpture in 

 which the concentric element predominates, with well-marked lunule 

 and escutcheon, the latter unequally divided between the valves, 

 larger in the left valve ; umbones plump ; ligament set in a groove ; 

 cardinals 3 in each valve, large, the middle left and the posterior two 

 right cardinals bifid, the left anterior lateral papilliform, obscure, 

 sometimes obsolete ; pallia! line with a small, short, rounded sinus : 

 inner margins of the valves crenulated. (Dall.) 



Distribution. Very wide. 



Fossil. Secondary and Tertiary. 



Subgen. 1. CIRCOMPHALUS. Morch, 1853. 



Circow lihrtlus (sp.), Herrmansen, Incl. Gen. Mai., i, 1847, 237 ; Morch, Cat. 

 Yoldi, 1853, 23 ; Dall, Trans. Wagn. Free Inst., iii, pt, ti, 1273. Type : 

 Venus plicata, Gmelin. Anaitis, Tryon, 1884 ; not of Duponchel, nor 

 of Rorner, 1857 (in part). Chiona, Rorner, 1857 ; not of Morch, 1853. 



Shell cordate, compressed, with distant elevated reflected lamina;, 

 more or less phyllate near the escutcheon ; lunule and escutcheon 

 impressed, sharply limited, striated, unequally divided between the 



