386 MAZATLAN UNIVALVES 



specific or only of sectional value (as will be learnt by induction 

 from more numerous specimens,) it bears the honoured name 

 of the author of the S3^nopsis of this genus in the Proc. Zool. 

 iSoc. 1843, pp. 159 et seq. Long.\"2A, long. spir. '98, lat.''21I, 

 div. 13". 



Sah. — Mazatlan ; 6 specimens, dead ; L'pool Col. 



Tablet 1836 contains 2 specimens, with extremes of sculpture. 



452. Myctrella sttbnodosa, ? n. s. 



31. t. "ilf. alhocinctce" forma et indole simili ; sed rufo-fusca, 

 albido tinctd ; suhlcevi, liridis radiantibus et striuUs extantibus 

 paucis spiralibus vix ornate, ; superficie Jiaud striata ; peri- 

 pherid subang^clatd, sulnodosd ; columella carina vix extante, 

 hand plicatd. 



Two specimens were found, agreeing in shape exactly with 

 T. albocincta, but with the faint spiral sculpture raised instead 

 of indented, the surface destitute of microscopic striulas, the 

 periphery subnodulous, and the keel surmounting the canal 

 very faint. Long. 1"22, long. spir. 1', lat. '36, div. 18". 



Hab. — Mazatlan ; extremely rare ; L'poQl Col. 



Tablet 1837 contains the large specimen, with the spire bent 

 through fracture. 



453. Myijeella eufocinebea, ?n. s. 



M. t. " M. Hindsii" forma et indole simili ; sed omnirio rufo- 

 cinered, haud maculatd ; cingulo latiore, pallidiore, margine im- 

 presso, tuber ciilos confertiores angnstos, magis elongatos gerente ; 

 costis radiantibus acuiis expressis, tuberculis lineis vix iindatis 

 convenientibus ; fascia circa 2}cripheriam valde rotundatam 

 pallidiore; columelld a car ind super canalem plicatd ; anfrac- 

 tibus subconvexis, lineis spiralibus, haud sculpturd microscopicd, 

 ornatis. 



In shape agreeing with M. Hindsii ; but with markings more 

 hke those of M. albocincta, yet destitute of minute sculpture ; 

 with the costa) much more developed, aud the sublinear tuber- 

 cles in a less waved line of junction. The cincture is marked 

 off by a deep suture. This, and the more rapid rounding of 

 tJie base, give the wliirls a slightly convex appearance. One 

 fresh, beautifully tinted specimen was found ; and a spiral 



