SHELLS. 251 



Are sometimes oblong, elongate, and regular, but are generally 

 distorted ; the regular ones are rarely white within, and their teeth 

 are always more oblique and less prominent than in the distorted 

 specimens. 



167. Venus Mesodesma. Quoy et Gaim. Voy. Astrol. 

 iii., 532, t. 84, f. IMS. 



Inhabits New Zealand. 



This shell varies in the degrees of its convexity, and the regu- 

 larity and height of the concentric ridges. 



168. Venus violacea. Quoy et Gaim. Voy. Astrol. iii., 

 533, t. 84, f. 19-20. 



Inhabits New Zealand. 



*169. Venus plumbea. Gmel, 3280. Crassatella incras- 

 sata, Lam. 



A Paris fossil ; was figured by Chemnitz as coming from New 

 Zealand. 



Fam. MACTRID.E. 



170. Mactra discors. Gray, Mag. N.H., L, 371. 

 Inhabits New Zealand, West Coast, N. Island. Dr. 



Dieffenbach. 



171. Sj)isula ovata. Gray, n. s. 



Inhabits New Zealand, West Coast, N. Island. Dr. 

 Dieffenbach. 



Shell ovate, ventricose, inequilateral, thin, slightly concentri- 

 cally wrinkled ; rounded in front, rather attenuated, and produced 

 behind ; white, covered with a thin pale brown periostraca, much 

 produced beyond the edge behind ; inside yellow ; lateral teeth 

 short, very high and subtriangular. 



172. Spisula elongata. Gt'ay. Mag. N. H., i., 271. 

 Mactra elongata. Quoy et Gaim. Voy. Astrol. iii., 

 518, t. 83, f. 1-2. 



Inhabits New Zealand. Quoy. 



173. Luiraria acinaces. Quoy et Gaim. Voy. Astrol. 

 iii., 545, t. 83, f. 5-6. 



Inhabits New Zealand. Quoy. 



