124 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Hyalina capsella, Tryon, Amer. Journ. Conch., II. 252 (1866). — \V. G. Binney, 

 L. & Fr.-AV. Sh., I. 76, Fig. 72 (1869). 



Mountains of Eastern Tennessee : a species of the Cumberland Subregion. 



Animal unknown. 



Formerly I referred as a synonyme to this species, Z. placentida, q. v., 

 describing and figuring the animal and dentition. I am, however, now con- 

 vinced of its diflerence. See below. 



Zonites placentula, Siiuttlewortii. 



Shell widely umbilicated, very much depressed, arctispiral, 

 very shining, marked by irregular, distant, impressed striae, 

 horn-color, diai)hanous, below of uniform color : whorls 7, most 

 gradually increasing, scarcely convex, the last convex below, 

 subexcavated around the umbilicus ; aperture oblique, lunate ; 

 peristome simple, acute. Greater diameter 7|, lesser 6^ mill ; 

 height, 3 mill. 



Near Z. demissus^ but most readily distinguished by its more 

 depressed shell, its wider umbilicus, and especially by the ab- 

 z placentula scnce of the heavy opaque white callus in the aperture on the 

 base of the last whorl (Shuttl.). 



Zonites -placentula, Siiuttlewortii, Bern. Mit. 1852, 194. — Gould in Terr. 

 Moll., III. 19. — Pfeiffer, Mon., III. 631. 



A species of the Cumberland Subregion, having been received from the moun- 

 tainous region of Tennessee (Jalapa, etc.) ; from Whitley County, Ken- 

 tucky, from Lexington, Virginia. I have also received it from the Hot Springs 

 of Arkansas, proving that it has the southwestern range beyond tiiis subregion 

 noticed in many of its species. It is also quoted, but I think incorrectly, from 

 Colorado by Ingersoll. 



Animal with distinct locomotive disk, longitudinal furrows, and caudal mucus 

 pore. 



Jaw as usual in the genus. 



The lingual membrane (PI. III. Fig. L) has 25 — 1 — 25 teeth, with 3 perfect 

 laterals, and 1 transition tooth. 



This species has been confounded with Z, capsella, but differs greatly in 

 many particulars, especially in its general outline, number of whorls, width of 

 umbilicus. There are sometimes 8 full whorls. 



Subgenus CONULUS, /Fitz.) Moq.-Tand. 



Animal (of Z.fidvus) bluish-black upon the head, neck, and eye-peduncles, 

 lighter on the sides and base ; foot very narrow, thread-like. A distinct caudal 

 mucus pore. 



Shell imperforate, or very narrowly perforate, turbinate, arcti-spiral ; whorls 

 5-6, rather convex ; aperture depressed-lunar, the penultimate whorl strongly 

 excided, somewhat oblique. Peristome with margins separated. 



