MAZATLAN UNIVALVES QA5 
Hab.—Mazatlan; extremely rare, off Spondylus and Chama ; 
LP’pool Col. 
Tablet 1157 contains the perfect specimen, and the youngest, 
with the ruge conspicuous. The other two specimens found 
were intermediate between these extremes. 
307. PVITRINELLA ANNULATA, 2. S. 
2V. t. subglobosd, solidiore, opacd, albé, anfractibus iv. et 
triente ; spird haud depressd, levi; carint spirali ad peri- 
pheriam conspicud, rotundata ; carinis duabus minoribus, acutis, 
quarun altera wnbilicum satis magnum definat, altera inter- 
media est; apertura subrotundata, & carinis subangulata, anfr. 
—penult. paruim attingente ; suturd subimpressa ; strits nonnullis 
spiralibus in spiram monstrantibus. 
This shell is somewhat solid and globose for the genus; and 
the nuclear portion not being clearly defined in the solitary 
specimen found, its position is doubtful. It is easily recog- 
nized by the rounded, annular keel on the periphery, with 
two somewhat sharp ones on the base, the latter bounding the 
umbilical region. Long. ‘027, lat. °052 by °047, div. 150°. 
Hab.—Mazatlan ; 1 sp. off Chama; L’pool Col. 
Tablet 1158 contains the specimen. 
308. VITRINELLA CINCTA, 7. 8. 
Vit. subglobosd, alba, anfractibus iv. tumidis ; carinis duabus 
majoribus, acutis, haud valde prominentibus, haud distantibus, 
utroque latere peripheria planate spiraliter cingentibus ; duabus 
quoque in bast minoribus ab wnbilico profundo, haud expanso, 
et peripheria equidistantibus ; spird subplanaté ; strtis passim 
spiralibus ; apertura & carinis angulata, anfr. penult. parum 
attingente ; regione inter umbilicum ipsum et carinam profunde 
concava ; anfractu ultimo parum declivt. 
The two principal keels are much closer and less prominent 
than in V. bifrontia. In the base it resembles V. annulata, 
but the spiral portion is quite different, being flattened, with 
very numerous spiral stria, The whirls do not enlarge rapidly. 
The umbilicus itself is somewhat narrow, with a broad funnel 
leading down to it from the nearest keel. The labium is some- 
what reflexed over it. Long. ‘02, lat. °034 by ‘028, div. 170. 
Hab.—Mazatlan ; 1 sp. off Spondylus ; Z’pool Col. 
Tablet 1159 contains the specimen. 
