MAZATLAN UNIVALVES 487 



GENUS NITIDELIA, Swains. 



Nitidella, Swains, (shell.) Mtidella, Gray, (operc.) 

 Buccinum, pars, Lam. 

 Columbella, pars, auct. 



Testa ut in Mitrelld (Risso, non Swains. H. fy A. Ad. Gen. 

 vol. i. p. 183 ;) interdum decollata ; labio continuo, hand crenato. 

 Operculum elongatum, nucleo laterali, ut in Purpuraformatum. 



The operculuin of the following species being distinctly 

 Purpuroid, it is necessary to remove it from both' Buccinum 

 and Columbella ; and as none of the genera in Purpuridse 

 seemed constituted so as to receive it, the above name (given 

 bv Swainson from the shell alone) was adopted by Dr. Gray 

 for such of the Columbellse as might prove to have Purpuroid 

 opercula. It did not seem expedient to adopt the group 

 of Messrs. Adams, till the opercula of other species had been 

 examined ; nor to draw out a more precise diagnosis, till it 

 was known how far the peculiarities of B. cribrarium were of 

 specific or_of generic value. 



^ 613. NlTIDELLA CKIBEAEIA. 



Buccinum cribrarium, Lam. An. s. Vert. vol. x. p. 176, 

 no. 43. Quo?/ fy G-aim, Voy. de VAstr. Zool. vol. ii. p. 421, 

 pi. 30, f. 21, 22. J&?. Icon Conch, p. 45, no. 44, pi. 16, f. 57. 



Columbella cribraria, Sow. Thes. Conch, p. 129, no. 51, pi. 37, 

 f. 112, 113. Desh. in Lam. loc. cit. Gray in Zool. Seech. 

 Voy. p. 129. B. M. Cat. Cub. Moll. p. 27, no. 316. Mke. 

 (Conch. St. Vine.) in Zeit.f. Mai. 1853, p. 75. 



(Columbella) Mitrella cribraria, H. fy A. Ad. Gen. i. 183. 



=Voluta ocelata, Gmel. p. 3455. 



=Le Barnet, Adans. Seneg. p. 146, pi. 10, f. 1. 



= Buccinum parvulum, Dkr. in Zeit.f. Mai. 1847, p. 64. 

 Phil. AbUld. iii. pi. 2, f. 7. 



== C. mitriformis, It rod. Sf King, Zool. Journ. Lister, Conch. 

 pi. 929, f. 24, (teste Gray.) 



= C. guttata, Sow. Proc. Zool. Soc. 1832, p. 118,Milll. Syn. 

 Nov. Test. Viv. p. 88. C. S. Ad. Pan. Shells, p. 89, no. 89. 

 (Non Sow. Proc. Zool. Soc. 1841, p. 50 : Thes. Conch. 

 p. 181, no. 59, pi. 39, f. 124 : = C. punctata, do. index, p. 146.) 

 This well marked form appears to be very widely diffused. 



The Pacific type is of course regarded by Prof. Adams as 



distinct from the Caribbean, as it was at first by Sowerby. It 



