244 



Transactions. — Zoology. 



rounded cardinal, and a strong bifid 



Fig. 7 



gin : length, 4 mm. ; 

 2J mm. from anterior 

 iii. = 85 ; vii. = 49 ; x. = 



height. 

 margin. 



= 58. ' 



°2 



crentdated cardinal below 

 and slightly in front of 

 it. Fig. 7 illustrates the 

 cardinals of the two 

 valves. The lateral teeth 

 are smooth ; the ligament 

 inset. Dimensions of two 

 specimens — Length, 

 mm. ; height 

 diam., 2 mm. ; beak 

 mm. from anterior mar- 

 mm. ; diam., 2 mm. ; beak 

 The mean of the indices is — 



ii 



3| mm. 



21 



Genus Corneocyclas, Ferussac (1818). 

 (= Pisidium, Pfeiffer, &c.) 



Subgenus Corneocyclas. 

 Nepionic shell convex, concentrically striated ; hinge with 

 two separate cardinals in the left, and a single compound, usually 

 arcuate, cardinal in the right valve. (Dall.) 



Sec. Corneocyclas, s.s. 

 Type : Tellina pusilla, Gmelin. 



Nepionic valves passing into the mature disc without any 

 strong demarcation ; the anterior cardinal and lateral adjacent 

 and retaining traces of their original connection : ligament 

 internal. (Dall.) 



Corneocyclas novozeelandica, Prime (1862). 



P.Z.S., 1862, p. 3. 



(1.) Lake ]Yaikare (Stat. 29— From weeds in H ft. to 2 ft.).— 



Nine specimens of different size ; colour greyish-yellow, shining, 



inequilateral, with fine concern lie 

 lines, which are crossed by close 

 microscopic radiate stria'. Nepi- 

 onic shell convex, concentrically 

 striated, well delimited, hut passing 

 without any change into the disc 

 of the adult valve. Ligament inset. 

 Right valve with the two cardinals 

 remaining united, crescent-shaped ; 

 four laterals. Left valve with two 

 cardinals, the posterior bifid, the 

 anterior triangular; two laterals. 



The accompanying fig. 8 shows the characters of the hinge. 



