MAZATLAN UNIVALVES : 395 
Sundo, ad aperturam contracto, spiram subascendente, callo 
parietali minore ; zone translucide carente. 
Two perfect specimens and one broken were found of this 
species, which resembles D. aspera, Hinds, and D. thiarella, 
Val. but does not accord in sculpture with either. Itis known 
at once from D. aterrima by the position of the slit, which is 
much nearer the suture and slopes upwards. This causes more 
of the tubercles to be seen on the spire. Long. °64, long. spir. *4, 
lat. °26, div. 35°. 
Hab.—Mazatlan ; 3 sp. only ; L’pool Col. 
Tablet 1897 contains the perfect specimen. In the young 
shell, the slit is quite close to the suture. 
463. Drintia zonunata, Pve. 
Pleurotoma cincta, Sow. Proc. Zool. Soc, 1833, p. 136. (Non 
Lam. An. s. Vert. vol ix. p. 347, no. 8:—Kien. Icon. Conch. 
p. 60, no. 38, pl. 19, f. 3. Mauritius.) 
Pleurotoma zonulata, Rve. Conch. Syst. 1848, pl. 234, f.10:— 
Conch. Ic. pl. 6, f.39.—C. B. Ad. Pan. Shells, p. 148, no. 184, 
Crassispira (Drillia) zonulata, H. § A. Ad. Gen. 1. 91. 
This pretty little species is known from D. aterrima, not only 
by the yellow neck-lace on the spire and the yellow belt on the 
base, but by the comparative smoothness of the infrasutural 
groove, and the shape of the tubercles, which are very narrow, 
but greatly elongated spirally. Long. °65, long. spir. °39, 
lat. °25, div. 35°. 
Hab.—Monte Christi and Xipixapi; in sand and gravel 7 fm. ; 
Cuming.—Panama; 2 sp. C. B. Adams.—Mazatlan; 1 sp.; 
P’pool Col. 
Tablet 1898 contains the specimen. 
464. DRILLIA MONILIFERA, 2. S. 
D. t. turritd, nigrad, aurantio gemmaté; anfr. subplanatis, 
omnino minutissime et confertissime spiraliter striulatis ; regione 
infra-suturali haud excavatad; strid jucta suturam vie tubercu- 
lata ; circa peripheriam zond aurantiacd, tuberculis parvis, 
circiter xii. ornata ; et infra, striis spiralibus, circiter v., tuber- 
culis minimis convenientibus ; tuberculis omnibus of strits 
plerumque aurantiacis ; apertura intus, nisi ad zonam subdia- 
phanam, purpureo-nigra, 
