248 MAZATLAN UNIVALVES 
Hab.—Mazatlan ; extremely rare, on Chama and Spondylus; 
LT’ pool Col. 
Tablet 1163 contains the perfect specimen. 
Genus PLIOTIA, Gray, 
Syn. B. M. 1840.—H. & A. Ad. Gen. vol. i. p. 404.—Phil. 
Handb. Conch. p. 206. 
Delphinula, pars, auct. 
The following shells are ranked doubtfully with this genus, 
not having the expanded lip of the typical species, and the 
opercula being unknown. 
313. P LiorTIa CARINATA, 7. S. 
2L. t. solidd, cinered, rufo tincta ; spird depressd, anfractibus 
lv. supra subplanatis, suturd distinctd, angulatd ; carinis iv. 
extantibus circa peripheriam ; liris spiralibus iii. in spird, 
nodulosis ; il. in bast rotundatd, haud extantibus ; circa wm- 
bilicuim magnum radiatim rugoso-nodosd ; apertura intus circu- 
lari, antr. penult. parum attingente ; anfractu ultimo valde 
decumbenie. 
Shell comparatively solid and opaque; it may be young, but 
from the small size of the nuclear portion and the sudden 
declension of the last whirl, it is presumed to be nearly mature. 
Long. °03, lat. °045 by °04, div. (anfr. penult.) 175° 
Hab.—Mazatlan ; 1 sp. on Spondylus; L’pool Col. 
Tablet 1164 contains the specimen, 
314. PLIOTIA STRIULATA, 7. s. 
?L. t. turbiniformi, svird subelevatd, albidd, solidd ; anfractt- 
bus 11. rotundatis, radiatim exillime et confertissime striulatis, 
carinis parum extantibus i. spiralibus ; umbilico magno ; m 
basi interdum rugis radiantibus ; apertura declivi, solidissiméa, 
intus rotundatd, anfr. penult. parum attingente. ; 
The thickness of this little shell is extraordinary, being at 
the posterior portion of the aperture nearly ‘005 in. The 
whirls are rounded, obscurely carinated, and most minutely 
and closely striated in the direction of growth. Long. °027, 
lat. ‘037 by ‘03, div. 130°. 
