292 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Fig. 189 shows the internal tubercle. 



Animal light-colored, head and eye-peduncles darker ; foot narrow, trans- 

 lucent, length little more than the diameter of the shell, pointed at the "end. 

 Eyes black, eye-peduncles 6 mill. long. Shell carried horizontally on the back. 



Jaw, as usual, with 8 ribs. 



Lingual membrane (Plate VII. Fig. B) with 27127 teeth; 9 perfect 

 laterals ; the eleventh tooth has a bifid inner cutting point. 



Plate XIV. Fig. H represents the genital system of this species. The penis 

 sac is very long, attenuated at either end, greatly swollen at the median third 

 of its length. The genital bladder is oval, on a short duct. 



Stenotrema labrosum, BLAND. 



Shell imperforate, lenticular, carinated, the carina somewhat obsolete behind 

 the aperture, solid, with curved striae, dark-brown colored beneath the epider- 

 mis ; epidermis thin, with prostrate hairs ; spire convex- 

 Fig. 190. conoid, obtuse ; whorls 5^, rather convex, the last deflexed, 

 constricted, the base inflated, and sculptured beneath the 

 epidermis with numerous impressed spiral lines ; the aper- 

 ture very oblique, narrowly ear-shaped, contracted by a 

 strong linguiform tooth extending along the entire parietal 

 wall; peristome callous, somewhat reflected, the margin 



ioined by a sinuous callus, the basal margin thickened, in- 

 S. labrosum, enlarged. " 



wardly much dilated, with a deep and wide notch in the 

 middle ; with an internal transverse tubercle on the base of the shell. Greater 

 diameter 12^, lesser 10 mill. ; height, 6| mill. 



Helix labrosa, BLAND, Ann. N. Y. Lye., VII. 430, PI. IV. Fig. 19 (1861). TV. 



G. BINNEY, L. & Fr.-W. Sh., I. 113 (1869). 

 Stenotrema labrosa, TRYON, Am. Journ. Conch., III. 59 (1867). 



A species of the Cumberland Subregion, ranging southerly into Alabama, 

 southwesterly into Arkansas. 



The thickened and reflected peristome, and deep wide notch, sufficiently 

 distinguish labrosum from Edgarianum. The notch in the latter, situated 

 in the centre of the aperture as in stenotrcmum, is, in a measure, obsolete, but 

 in labrosum it is strongly developed, and nearer to the outer edge of the peri- 

 stome, as in hirsutum. The form of the parietal tooth of this species is like 

 that of hirsutum, while Edgarianum is in that particular more like stenotre- 

 mum. Edgarianum, in fact, connects stenotremum with spinosum, but labro- 

 sum is rather allied to hirsutum, and in the character of the peristome to 

 maxillatum. 



Jaw with 12 ribs. Lingual membrane with 351 35 teeth, 12 of which 

 are laterals. (PI. XVI. Fig. T.) 



Genitalia as in monodon. 



