]:ahtern rKOYixcE — iateriok region species. 301 



iuseited on the vas delereius near its jnuetioii with the peuis sac; the 

 genital bladder is long', stont, blunt at its summit; its duct is very nar- 

 row at its entrance into the bladder for a short i^ortion of its course, 

 then becomes suddenly expanded into very much the shape and still 

 greater size of the bladder. This peculiar arrangement of the genital 

 bladder and its duct forms a good specific character distinguishing 

 aJbolabris from cxoleius and other species. I have found its characters 

 constant in the numerous individuals I have examined. As it is want- 

 ing in the figure given by Semper (Phil. Archip., Plate XIV, Fig. IG), 

 I am inclined to doubt the identity of his specimen. Lehmann (Mai. 

 Bliitt., XI, Plate I, Fig. 1, 1864) no doubt drew his figure from a true 

 (dholahris. 



The figure of the jaw given by Leidy represents it imbedded in the 

 tissues of the head above. 



Mesodon ABidrewsi, W. G. Binney. 



Shell imperforate, globose, with delicate wrinkles of growth and 

 microscopic revolving stride, horn-color; spire ele- 

 vated, conic, apex obtuse; whorls 0, convex, the 

 last greatly swollen ; peristome white, thickened, 

 slightly reflected, ends separated, the columellar one 

 expanded. Greater 4i"nH'ter 25, lesser 20"""; height, 

 14™-". 



Mesodon Andreirsi, W. G. Binney, Ann. N. Y. Acad. Sc.,i, 360, 

 pi. XV, fig. i^is-y). 



Eoau Mountain, IMount Mitchell, Xorth Carolina 

 (Mrs. Andrews). Hayesville, X. C; Toccoa Falls, 

 Georgia; Tallnlah Falls, Georgia: Habersham County, 

 Georgia (Hemphill). A specie of the Cumberland Subregion. 



It can hardly be said to resemble closely any known species, though 

 somewhat like a gigantic il7. MiicheUianvs. 



Jaw with IG libs. 



Lingual membrane [1. c, Plate XIV, Fig. F) long and narrow; teeth 

 G4-1-G4:, with about 15 laterals on either side. The centrals and laterals 

 have no side cusps or cutting points, and only on the extreme margi- 

 nals does a side cutting point appear. The dentition is like that of 

 chinsus and thyroidcs, with long cutting points. 



