MAZATLAN UNIVALVES 497 



theless the points of difference above indicated being constant, 

 it did not seem allowable to unite them completely. Long. '63, 

 long. spir. '28, lat. '4, div. 50. 



Hah. Mazatlan ; extremely rare ; L'pool Col. 



Tablet 2393 contains a sp. kindly presented by J. W. White- 

 head, Esq. of Liverpool. 



625. NASSA (? PAGODUS, var.) ACUTA. 



N. t. pagodiformi, albidd, rubrofusco tinctd, intus violascente ; 

 anfr. nucleosis iii. Icevibus ; dein anfr. vi. normalibus, valde 

 tumentibus, suturd parum excavatd, a costis undulatci ; costis 

 radiantibus circiter ix. haud latis, Jiaud acutis, color e intensiore, 

 interstitiis latis ; costis ultimis antice subobsoletis ; lirulis 

 spiralibus crebris, extantibus, costis superantibus, supra costis 

 subtuberculosis ; aperturd subguadratd, antice lata ; labro et 

 labio acuto, extantibus, haud reflexis ; labro antice sinuato, ad 

 dorsum varicoso f intus ienue lirato, lira ultima juxta canalem 

 extante ; labio lira parietali conspicud, plica juxta canalem 

 valde extante, alter d subobsoletd; canali valde intorto, con- 

 spicuo ; operculo serrato. 

 Comp. Triton pagodus, Rve. Condi. Ic. pi. 20, sp. 97 :=Nassa 



p. C. B. Ad. Pan. Shells, p. 63, no. 50. 

 Comp. Buccinum decussatum, Kien. Icon. Conch, p. 109, 



no. 106, pi. 30, f. 3 : = (Nassa) Hima decussata, R. fy A. Ad. 

 Gen. i. 121. 



The very beautiful Mazatlan shells were at first identified 

 with an E. Indian species in the Cumingian collection, which 

 may be the true N. polygonata of Lam. This however differed 

 from the species as figured by Kien. ; and, there being no 

 W. Coast shell among Mr. Cuming's Nassse at all resembling 

 it, the N. acuta was described as new. But the Triton pagodus 

 has evidently so much in common, that a collation of types 

 (at present impossible) may prove them identical. If so, the 

 error must be attributed to the unfortunate location of this 

 very decided Nassid among the Tritons. Kiener's species, 

 assigned by him to Africa, is identified with the Pacific shell 

 by Prof. Adams : it may however be an analogous species, as in 

 the case of N. tiarula and N. tegula. A dwarf adult, possessing 

 the ordinary number of whirls, and a normally-sized mucleus, 

 measures '53 by *36 ; the largest sp. measures long. "83, 

 long. spir. '44, lat. *6, div. 60. 



