MAZATLAK UNIVALVES 497 



theless the points of difference above indicated being constant, 

 it did not seem allowable to unite tliem 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. Nass a (? PAGODUS, var.) AcrTA. 



N. t. pagod^formi, albidd, ruhrofusco tincta, intus violascente ; 

 anfr. nucleosis iii. lavihus ; dein avfr. vi. normaUhns. valde 

 tumentihus, sutura parum excavatd, a costis undulata ; costis 

 radiantihus circiterix. haud latis, haud acutis, colore intensiore, 

 interstitiis laiis ; costis xiltimis antice suhohsoletis ; /irulis 

 spiralihus crebn's, extantibus, costis superantibus, supra costis 

 subtuberculosis ; aperturd subquadratd, antice lata ; labro et 

 lahio acuto, extantibus, haud rejlexis ; labro antice simiato, ad 

 dorsum varicoso. intus tenue lirato, lira ultima juxta canalem 

 extante ; labio lira paHetali conspicud, plied juxta canalem 

 valde extante, altera subobsoletd ; canali valde intorto, con- 

 spicuo ; opercitlo serrato. 



Comp. Triton pa^odus, Bve. Conch. Ic. pi. 20, sp. 97 : = 1^3888 



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, H. Sf A. Ad. 



Gen. i. 121. 



The very beautiful Mazatlan shells were at first identified 

 with an E. Indian species in the Curaingian 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 a.s 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 Triton.s. Kienor's species, 

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

 by Prof. Adams : it may howf*"er be an analogous species, as in 

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

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

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

 long. spir. '44, lat. '6, ^^v. 60". 



