MAZATLAN UNIVALVES 433 
(c.) Ribs continuous over the base. 
534. CHEMNITZIA TENUILIRATA, 2. S. 
Ch. t. elongata, angustd, albidé ; vertice nucleoso haud 
extante, marginibus spire rectis haud superante; anfr. (testa 
guniore) V1., planatis, suturd angustd, distinctd ; lirulis circiter 
xxiv. vectis, &@ basi ad apicem ascendentibus, circa basin con- 
tinuis ; interstitiis linets curvatis decussatis ; labro acuto, 
labio tenwt, columellé gracili. 
The species is described from a perfect: young and a broken 
p p y gs 
adult specimen. ‘The latter, when complete, must have 
measured about ‘23. The young one measures Jong. *063, Jong. 
spir. 045, lat. °027, div. 15°: (¢. adultd, 11°.) 
Hab.—Mazatlan ; 2 sp. off Spondylus; L’pool Col. 
Tablet 2005 contains both specimens. 
535. CHEMNITZIA UNIFASCIATA, 7. $. 
Ch. t. tereti, angustd, flavescente, fascid densius coloraté in 
medio anfractuum spiran ascendente ; vertice nucleoso helicoideo, 
satis magno, marginibus spire rectis vix superante, haud pros 
minente, anfr. 1. subglobosis, verticaliter sitis, apice parum 
conspicuo ; anfr. normalibus planaiis, suturd haud conspicud ; 
lirulis minimis vectis, acutis, circiter xx. circa basin prolonga- 
tam rotundatam continuis ; striulis spiralibus decussantibus, 
in spird 1v., in bast crebrioribus ; aperturd elongata ; columella 
vie contorta ; 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. B. Ad.: but the 
upper whirls are much flatter. The only specimen found has 
5 normal whirls, and measures long. ‘09, long. spir. *08, 
lat. ‘025, div. 18°. 
Hab.—Mazatlan; 1 sp. off Spondylus; L’pool Col. 
Tablet 2006 contains the specimen. 
Suscenus DUNKERIA. 
Chemnitzia, anfractibus tumidis, decussatis. 
This group combines the characters of Chemnitzia and Aclis, 
presenting the mouth of the former with the rounded whirls 
Dec, 1856. 00. 
