110 A MANUAL OF AMERICAN LAND SHELLS. 



nals is very gradual, the latter being a simple modification of the former. 

 My figures give a central with the first, sixteenth, and thirty-first teeth. 

 They are of the usual type. 



The nervous ganglia and the digestive system present no peculiar 

 features^ The genitalia are figured on Plate XI, Fig. B, of Terr. Moll., 

 V. The penis sac is long, narrow, tapering to its apex, where it re- 

 ceives the vas deferens ; the retractor muscle is inserted below the en- 

 trance of the latter. The genital bladder is oval, on a long, narrow 

 duct. There is a small, sac-like, accessory organ, probably a dart sac. 



ids). 



HEMPHILLIA. 



Animal limaciform, blunt in front, swollen at center, tapering behind. 

 Fig. 75. Mantle subcentral, large, oval, greatly produced in 



front, freQ around its margin, and concealing all but 

 a rounded, large orifice, an internal sbell-plate. No 

 distinct locomotive disk to foot. Lines of furrows 

 cootractedli'n spirits, mu near and parallel to edge of foot, rising above 

 the extremity and apparently uniting over a transverse mucus slit, 

 overhanging which is a greatly x>roduced horn-shaped process. Res- 

 piratory orifice at right edge of mantle, near its center. Generative 

 orifice at right side of neck, near right eye-peduncle. 



Shell-plate horny, small, unguiform, longer than wide, with posterior 

 nucleus and concentric lines of growth, exposed except at its edges, 

 which are covered by the mantle. 



Jaw wide, low, slightly arcuate ; ends blunt, but little attenuated ; 

 anterior surface with numerous ribs denticulating either margin. 

 Fig. 7fi Liugual membrane described below under 



77. ylandulosa. ^'"' ^^' 



Oregon Region, at Astoria. 

 inteTmai ^^^^ curious slug, by its general outline 

 ^^^Xn- and by the form and position of its shell, ^ giaZuiosa. 



may be compared to Omalonyx and Amphib- 

 ulima. The former has, however, a jaw with the supplementary ex- 

 tension as in Succinea, the latter has the jaw usual in Bulimulus and 

 CyUridrella, while neither of them has the prolongation of the mantle. 

 Both of those genera also are readily distinguished by their shell being 

 more developed ancj approaching a spiral form. 



Hyalimax is distinguished from ffemphiWa by its Succinea-like jaw. 

 Otherwise it resemblos our genus in its general outward appearance 

 and by it§ ooa-spiral sJjell. This shell, however, in Eyalimax is almost, 



