336 BULLETIN OF TttE 



Mesodon Sayii, Binnet, var. Chilhoweensis. 



An opportunity of examining the animal of this large form of M. Sayii, for 

 which I am intlebted to Dr. Lewis, shows that the genital system (PL H. 

 Fi". I) is similar to that of the typical form, excepting that the penis sac is 

 still more developed, surpassing by three times the whole genital system in 

 length. (See Terr. Moll. U. S., V., PI. XL Fig. 11.) 



The jaw and lingual dentition are the same as in the typical Sayii. I have 

 figured on PI. I. Fig. K, the dentition of this variety. 



Mesodon devia, Gould. 



Freeport, Cowlitz Co., Washington Territory, Mr. Henry Hemphill. On 

 PI. IL Fig. G, I have figured the genital system of the typical form of this 

 species : a is the penis sac ; b, the genital bladder and duct. 



Pomatia Humboldtiana, Val. 



The individual examined was considerably smaller than Fig. 1, PI. XL of 

 Mollusques Terr, et Fluv. du Mexique. It was collected by Dr. E. Palmer. 



The genital system is figured on PL II. Fig. J. The genital bladder {g. b.) 

 is small, on a long narrow duct ; the penis sac (p. s.) is long, tapering to a 

 flagellate point, and receives the vas deferens (v. d.) about its middle ; there is 

 a prostate gland (pr.) on a short peduncle, globular, with four accessory leaf- 

 lets clinging to its base, giving a general rosette-like form to the gland. 



The jaw is short, arched, bluntly ending, with six broadly separated stout 

 ribs denticnlating either margin. 



The lingual membrane is long and narrow. Central teeth (PI. II. Fig. 

 K) pear-shaped, with no side cusps or cutting points ; laterals like the cen- 

 trals, but asymmetrical ; marginals with one long inner bifid cutting point 

 and one smaller side cutting point. 



Ochthephila tiarella, Webb & Berth. 



Madeira. Dr. Hillebrand to Dr. Newcomb. The species is rarely found 

 living. 



Jaw low, slightly arcuate, ends scarcely attenuated ; anterior surface with 

 about 15 flat, broad, crowded ribs, scarcely denticnlating the cutting margin. 



Lingual membrane with 21-1-21 teeth of same type as Plebecula Zun'c/a, q. v. 

 Laterals about 9 on each side of the central. 



Ochthephila abjecta, Lowe. 



Madeira. Dr. Hillebrand to Dr. ISTewcomb. 



Jaw low, slightly arcuate, ends attenuated ; cutting edge with a blunt 

 median projection ; no anterior ribs. 



Lingual membrane with 24-1-24 teeth, of wliich about 4 on each side are 

 laterals. Teeth of same type as those of Plebecula lurida, q. v. 



