MAZATLAN UNIVALVES 395 



fundo, ad aperturam contracto, spiram subascendente, callo 

 parietali minore ; zonce translucidce carente. 



T\vo perfect specimens and one broken were found of this 

 species, which resembles D. aspera, Hinds, and D. thiarella, 

 Vol. but does not accord in sculpture with either. It is 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. DBILLIA ZONULATA, five. 



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, pi. 19, f. 3. Mauritius.) 

 Pleurotoma zonulata, Rve. Conch. Syst. 1848, pi. 234, f. 10 : 



Conch. Ic. pi. 6, f. 39. C. B. Ad. Pan. Shells, p. 148, no. 184. 

 Crassispira (Drillia) zonulata, H. fy A. Ad. Gen. i. 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. 

 Hal. Monte Christi and Xipixapi ; in sand and gravel 7 fm. ; 



Cuming. Panama ; 2 sp. C. B. Adams. Mazatlan j 1 sp. ; 



L'pool Col. 



Tablet 1898 contains the specimen. 



464. DEILLIA MONILIFEEA, n. s. 



D. t. turrita, nigra, aurantio gemmatd ; anfr. subplanatis, 

 omnino minutissime et confertissime spiraliter striulatis ; regione 

 infra-suturali hand excavatd ; stria juxta sutler am vix tuber cu- 

 latd ; circa peripheriam zona aurantiacd, tuberculis parvis, 

 circiter xii. ornatd ; et infra, striis spiralibus, circiter v., tuber- 

 culis minimis convenientibus ; tuberculis omnibus et striis 

 plerumque aurantiacis ; apertwrd intus t nisi ad zonam subdia- 

 phanam, purpureo-nigrd. 



