Suter. — On New Zealand Mollusca. 243 



hardly to be distinguished from the later growth, obtuse ; an- 

 terior side of shell slightly produced, rounded, posterior side 

 broadly convex ; the whole of the valves concentrically finely 

 striate. Ligament inset. Left valve with a straight lamellar 

 upper cardinal, and below and slightly in front of it a curved 

 stouter tooth. In the right valve the two cardinals are united, 



forming an oblong squar- 

 ish tooth with three deli- 

 ct, ticulations on the lower 

 margin. Laterals smooth. 

 Fig. 5 illustrates the car- 

 dinal teeth of the two 

 valves. Length, 5 mm. ; 

 height, 44; mm. ; diam., 

 2§ mm. Umbo 3 mm. from 

 anterior end. The indices are — iii. = 85 ; vii. = 55 ; x. = 60. 



This is no doubt the same as S. lenticula, Dunker, as 

 Hochstetter obtained the specimens from the lakes Rotoiti 

 and Taupo, and I consider it as a synonym of S. novce-ze- 

 landice. 



(2.) Lake Taupo (Stat. 4 — Dredged with weeds in 20 ft., 

 and from bottom of coarse pumice in 100 ft.). — Four specimens 

 of straw colour, the nepionic shell rather distinct, but otherwise 

 not differing from the typical form. Right valve with two 



minute cardinals, the anterior oblong, 

 -^^^2^% the posterior short, triangularly oval, 

 a -"■ "^ p elevated. Left valve with two minute 



R ■ v teeth, broadly rounded behind, pointed 



at the anterior end, one in front of the 

 other. Fig. 6 shows the form and posi- 

 tion of the cardinals. Length, 4^ mm. ; 

 height, 4 mm. ; diam., 2J mm. Umbo 

 2| mm. from anterior end. Indices — 

 iii. -84-89; vii. = 56; x. = 61. 



(3.) Lake Taupo (Stat. 34 --With weeds from 20 ft. to 

 §0 ft,). — Six small specimens, a little more oval and com- 

 pressed, but otherwise the same as the examples from Stat. 4. 

 Length, 4 mm. ; height, 3 mm. ; diam., If mm. These are 

 the dimensions of Dunker's S. lenticula. Indices — iii. = 75 ; 

 vii. = 44. 



(4.) Lake Waikaremoana (Stat. 33— Dredged in 10 ft. to 20 ft.). 



There are twenty-three small to minute specimens. The 



larger examples are yellowish- grey, the small ones straw-colour. 

 In the right valve there are two lamellar cardinal teeth meeting 

 at an obtuse angle ; in the left valve there is one crescent-shaped 



