MAZATLAN UNIYALVES 433 



(c.) Ribs continuous over the base. 



534. CHEMNITZIA TENUTLIEATA, n. s. 



Ch. t. elongatd, august a, albidd ; vertice nucleoso haud 

 extante, marginibus spirce rectis haud superante ; anfr. (testa 

 juniore) vi., planatis, suturd angustd, distinctd ; lirulis circiter 

 xxiv. rectis, a basi ad apicem ascendentibus, circa basin con- 

 tinuis ; inter stitiis lineis curvatis decussatis ; labro acuto, 

 labio tenui, columelld gracili. 



The species is described from a perfect young and a broken 

 adult specimen. The latter, when complete, must have 

 measured about "23. The young one measures long. '065, long, 

 spir. '045, lot. '027, div. 15: (t. adultd, 11.) 

 Hob. Mazatlan; 2 sp. off Spondylus ; L'pool Col. 



Tablet 2005 contains both specimens. 



535. CHEMNITZIA UNIFASCIATA, n. s. 



Ch. t. tereti, angustd, Jlavescente, fascia densius coloratd in 

 media anfractuum spir am ascendente ; vertice nucleoso helicoideo, 

 satis magno, marginibus spirce rectis vix superante, haud pro* 

 minente, anfr. ii. subglobosis, verticaliter sitis, apice parum 

 conspicuo ; anfr. normalibus planatis, suturd haud conspicud ; 

 Itrulis minimis rectis, acutis, circiter xx. circa basin prolonga- 

 tam rotundatam continuis ; striulis spiralibus decussantibus, 

 in spird iy., in basi crebrioribus ; aperturd elongatd ; columelld 

 vix contortd ; labio valido. 



The spiral band of colour can only just be seen in a good 

 light, the shell probably being dead ; but it is the only Mazat- 

 lan species which possesses the character. In some respects it 

 resembles the W. Indian Ch. reticulata, C. IB. Ad. : but the 

 upper whirls are much natter. The only specimen found has 

 5 normal whirls, and measures long. '09, long. spir. *06, 

 lot. '025, div. 18. 

 Hab. Mazatlan ; 1 sp. off Spondylus ; L'pool Col. . 



Tablet 2006 contains the specimen. 



SUBGENUS DUKKEBIA. 



Chemnitzia, anfractilms tumidis, decussatis. 



This group combines the characters of Chemnitzia and Aclis, 

 presenting the mouth of the former with the rounded whirls 

 Dec. 1856. oo. 



