MUSEUM OF COMPARATIVE ZOÖLOGY. 107 
The jaw is of the same type as described under P. Lansing?, with over 19 
ribs. (Suppl., Plate II. Fig. O.) 
The peculiar lingual membrane also is the same as in that species, with four 
laterals on each side of the central tooth. (Suppl., Plate I. Fig. N.) 
Punctum, Morse. 
Animal as in Patula. 
Shell minute, umbilicated, thin, horn-colored, depressed globose; whorls 4, 
the last not descending ; spire slightly elevated ; aperture rounded ; peristome 
thin, acute. 
Europe and North America. 
Jaw slightly arcuate, ends blunt, not acuminated, composed of numerous , 
subequal, overlapping distinct plates. 
Lingual membrane as usual in the Helicide ; bases of attachment sub- 
quadrate, reflection small, tricuspid in the centrals, bicuspid in the laterals, 
marginals irregularly denticulated. 
Distinguished by the peculiar free plates of the jaw. 
There are two species of Punctum, conspectum and pygmaum. 
Helicodiscus fimbriatus, Wrernersy, var. salmonaceus, HEMPHILL. 
Plate III. Fig. 8. 
I give a figure of this variety from an authentic specimen. See 3d Suppl., 
p. 189. 
Anadenus, HEYNEMANN. 
Animal limaciform, subeylindrical, tapering behind ; tentacles simple; man- 
tle anterior, concealing an internal shell-plate ; no longitudinal furrows above 
the margin of the foot, and no caudal mucus pore ; a distinct locomotive disk ; 
external respiratory and anal orifices on the right posterior margin of the 
mantle; orifice of combined genital system behind and below the light eye- 
peduncle. (See Plate I. Fig. 1.) 
Internal shell-plate small, oval, flat, with posterior nucleus and concentric 
striæ. (See Plate.) 
Jaw with numerous ribs. See Plate TII. Fig. 5. 
Lingual membrane with tricuspid centrals, bicuspid laterals, and quadrated 
marginals. (See same.) 
Differs from Prophysaon by its posterior respiratory orifice, by the position 
of the genital orifice, and by its locomotive disk. 
Himalaya Mountains ; recently found in San Diego County, California, by 
Mr. Hemphill. 
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