252 MAZATLAN UNIVALVES 
which covers the umbilicus, leaving only a slight chink. A 
second sp. agrees in all respects except that the spiral sculp- 
ture is coarse and somewhat moniliform; but it is too much 
weathered to decide on its affinities with confidence. Long. 019, 
lat. ‘039 by °034, div. 153°. 
Hab.—Mazatlan ; 2 sp. off Chama and Spondylus ; Z’pool Col. 
Tablet 1170 contains the typical specimen. 
320. ETHALIA PALLIDULA, 2. s. 
LE. t. globosd, solida, alba; ad spiram planata, ad basim pro- 
ducta ; anfractibus ii1., suturd indistincta, apice planaté ; tota 
superficie striis spiralibus subrugulosis impressd ; callositate 
minima ; umbilico nullo; apertura elongaté, ad basim sub- 
angulata ; labro acutiore, labio conspicuo. 
A little globular shell, produced at the base of the columella, 
and presenting the general aspect of the young of Lacuna 
pallidula. Itis on the extreme verge of the genus, the com- 
pact spire preventing the development of the callus. Long. ‘029, 
lat. ‘044 by °035, div. 170°. 
Hab—Mazatlan ; 1 sp. off Spondylus; ZL’pool Col. 
Tablet 1171 contains the specimen. 
321. ETHALIA CARINATA, 7. s. 
EF. t. discoidali, planata, aurantio-fuscéd ; anfractibus iv. et 
dimidio, quarum i. primi leves, vix amplectentibus, sutura 
valde impressa ; sub peripheriam acute carinaté ; totd super- 
Jicie rugulis incrementi confertissimis ornata ; regione umbilicalr 
concava ; callositate spirali elongata, angustd, rimam conspicu- 
am umbilicalem gyrante,juxcta labium parum planatd ; apertura 
subquadrata, sinuatad, & carind angulata ; labio ad parietem 
nullo ; labro intus suturam parum calloso. 
This charming little shell has the general aspect of Planorbis 
carinatus, but with the whirls a very litile elevated, and the 
keel just below the centre. The whirls very slightly embrace, 
but are cemented by the long, thin callus. Both above and 
below, it is covered with extremely close, rugulous, radiating 
striule. In its mode of growth it affords a transition to Teino- 
stoma. Long. 013, lat. ‘038 by 033, div. 175°. 
Hab.—Mazatlan ; 2 sp. off Spondylus ; L’pool Col. 
Tablet 1172 contains the freshest (but smallest) specimen. 
