238 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



respiratory orifice ; it differs in having an internal shell, in the position of its 

 generative orifice, and by the want of a caudal mucus pore. The genus is also 

 allied to Ariolimax in having a ribbed jaw, quadrate marginal teeth to its 

 lingual membrane, and an internal shell; it differs in the position of both 

 genital and respiratory orifices, and by the want of a caudal mucus pore. The 

 absence of a distinct locomotive disk to the foot distinguishes our genus also 

 from Arion, Limax, and Ariolimax. It is not readily confounded with any other 

 known American genus. The Irish genus Geomalacus is somewhat allied, 

 having an anterior respiratory orifice and an internal shell, and quadrate 

 marginal teeth. Geomalacus, however, differs from Prophysaon in having an 

 extremely anterior mantle and orifice of respiration close behind the right 

 tentacle. It also has a locomotive disk and caudal mucus pore. 



Prophysaon Hemphilli. 



Body blunt anteriorly, attenuated posteriorly, rounded and high on the back. 

 Mantle granulated, whitish with a circular ring of smoke-color above the res- 

 piratory orifice. Body obliquely reticulated with bluish lines, the reticulations 

 larger (about twelve) below each side [of the mantle, more numerous and 

 smaller on the posterior extremity of the body. These reticulations are sub- 

 divided by irregularly disposed, rounded tuberosities, with colorless interstices. 

 Above the foot, from the longitudinal line running around the animal to the 

 edge of the foot, are perpendicular lines or furrows, also bluish in color. The 

 foot has crowded wrinkles, running obliquely backwards from its centre to its 

 margins. Length of an alcoholic specimen, 40 mill. (See Fig. 137.) 



Prophysaon Hempliilli, BLAND and W. G. BINNEY, Ann. Lye. Nat. Hist, of 

 N. Y., X. 293, PI. XIII. Fig. 8 (1873). 



Forest Grove and Astoria, Oregon ; the variety at Oakland and Mendocino 

 County, California ; thus it is found in the Pacific Province. 



The internal shell (Fig. 139) differs in thickness, but is always well marked, 

 sometimes suboval, sometimes subhexagonal, always longer than wide. 



The jaw and lingual membrane (PI. V. Fig. I) have been de- 

 Fig. 139. scribed above. 



0The genitalia are figured on PL XII. Fig. H. The testicle is 

 composed of black aciniform caeca ; it is almost completely buried 

 in the upper lobes of the liver, the epididymis completely so, lying 

 on the floor of the cavity formed by the spiral winding of the 

 upper lobes. It appears to pass through one of the lower lobes to 

 P.Htmpkilli. join the oviduct, before reaching which it is greatly convoluted. 

 The accessory gland of the epididymis appears to be composed of 

 several aciniform caeca of unequal size. The prostate gland is large. The 

 vas deferens is extremely long, ten times as long as the penis, and equals the 

 length of the whole genital system. It is attached to the side of the vagina 



