EASTERN PKOVINCE IKTERIOK REGION .SPECIES. 305 



onyniy will show. It is, however, well kuowu iiuder its correct name 

 by meaus of the figures published by Binuey, Keeve, and Chemnitz, 

 ed. _;. Deshayes is the only one who has figured it under a wrong 

 name. 



Bland has carefully and correctly arranged the synonymy in his 

 valuable " i^otes," I. c. 



Pfeiffer adds doubtfully to the synonymy H. tkyroides var. edentula 

 of Beck, Ind., p. 23. 



Jaw very arcuate, of uniform width ; ends blunt ; anterior surface 

 with 11 stout, crowded ribs, deuticulating either margin. 



Lingual membrane (Terr. Moll., V, Plate YIII, Fig. E) with 40-1-40 

 teeth ; 13 perfect laterals. Morse counted 120 rows of 39-1-39 teeth. 

 The outer laterals have the side cusp decidedly developed. 



The upper portions of the genital system (Terr. Moll., V, Plate XV, 

 Fig. G) not observed. The penis sac is long and slender, with the vas 

 deferens and retractor muscle entering its apex and its orifice entering 

 the vagina near its base. The genital bladder is long, stout, cylindri- 

 cal, with a median contraction ; its duct is hardly distinct from it, with 

 an entrance oi)posite that of the penis sac. The prostate is very large. 



The animal of this and many other species is often overrun with 

 great numbers of Acari resembling Amrus limacum of Europe. There 

 appears to be at least two species of them. They are very minute, 

 tlesh-colored, and move with great rapidity, often entering and coming 

 out of the respiratory foramen. Their presence does not seem to cause 

 any uneasiness nor even to be felt by the snail.* 



MesodoBi JTIitclielliuiius, Lea. 



Shell imperforate, depressed, conoid globose, thin, with crowded 

 striie and very crowded, decussating, microscopic lines, 

 pellucid, horn-color, polished ; spire brietly conoid ; 

 whorls 5. moderately convex, gradually increasing, the i^ 

 last ventricose, subconstricted and briefly deflected an- 

 teriorly' ; aperture diagonal, lunate, subperlaceous ''^' ^"'''''"''""'""'' 

 within ; peristome white, thickened, its terminations slightly converg- 



FlG. 325. 



* Hi/jiojyus concolur, Halde^iax. Oval, nearly colorless or very pale 

 ochraceous ; bristled ; sides impressed. Length, 0.4"'™. 



Diflers in outline from the European species, whicli it resembles in 

 general appearance, mode of life, and in tlio. large pair of projecting 

 setie anteriorly and posteriorly. A colored dorsal line luis been ob- 

 served. 



1749_Bull. 28— —20 



