992 PELECYPODA. [Eulrnndlibranchia. 



of brown. Beaks not much raised, tumid, approximate, incurved 

 and turned forwards, sharply pointed. Anterior end very little shorter, 

 narrowly convex, the dorsal margin a little excavated and slowly 

 descending ; posterior end subtruncate, the dorsal margin long, lightly 

 convex, slowly descending ; basal margin broadly rounded. Lunule 

 narrow, lanceolate. Escutcheon narrow, concave, finely striate. 

 Sculpture consisting of equal narrow and flat concentric riblets with 

 linear interstices, on the posterior end two ribs usually merge into 

 one stronger and slightly raised rib ; radial striation is but faintly 

 indicated. Colour whitish or light brown, generally with a few 

 radiate bands of darker brown, or variably and often beautifully 

 ornamented with zigzag lines. Interior bluish-white in the centre, 

 more or less violet round the margins. Margins finely crenulate. 

 Hinge strong but short ; right valve with 3 divergent cardinals, the 

 anterior feeble, the two others stronger and lightly grooved ; left 

 valve with the 3 diverging cardinals nearly of equal strength, the 

 posterior tooth longest and a little thinner, the median tooth a little 

 grooved. Ligament moderately strong, short, deep. Adductor-scars 

 subequal, the anterior oval, the posterior roundish. Pallial sinus 

 very short, triangular, free, ascending. 



Length, 20-25 mm. ; height, 15-75 mm. ; diameter, 9 mm. (type). 



Type in the Mus. Hist. Nat., Paris. 



Hob. Throughout New Zealand, from the shore to about 50 

 fathoms ; more abundant in the north. Auckland Islands ; Ker- 

 madec Islands (Captain Bollons). Tristan da Cunha, in 1.000 fathoms 

 (" Challenger" Exp.). 



Fossil. -Miocene and Pliocene. 



Subsp. violacea, Quoy and Gaimard, 1835. 



Venus violacea, Q. & G., Voy. Astrol., iii, 1835, 533, pi. 84, f. 19, 20. Chime 

 mesodesma violaci/i, (). & G. : Suter, P. Mai. S., vi, 204. 



The shell is small, much compressed, subequilateral ; the lunule 

 shorter than in the species, but of about the same width ; the colour 

 is a reddish-violet, the beaks reddish, with 2 rays of green with white 

 spots descending from the beaks, one nearly vertical, the other ending 

 at the posterior end of the ventral margin. 



Length, 15-75 mm. ; height. 12-25 mm. ; diameter, 6-75 mm. 

 (type). 



Type in the Mus. Hist. Nat., Puns. 



#&. New Zealand (Q. & G.) ; Tiri-Tiri Island (H. S.). 



Genus 2. GOMPHINA, Morch, 1853. 



Gomphina, Morch, Cat. Yoldi, ii, 1853, 19. Type : Venus donacina, Chem. 

 Goin i>liin<i. Dall, Trans, Wagn. Free Inst., iii, pt. 6, 1289; Jukes-Browne, 

 P. Mai. S., viii, 243. 



Shell trigonal, rather thick, compressed, smooth or concentrically 

 striated. Lunule long, narrow, superficial, and feebly circumscribed ; 



