394 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



The variation in the globoseness of the whorls, and consequent outline of the 

 shell, may be judged from the following measurements of two specimens : 

 diameter 18, length 25 mill.; diameter 7, length 19 mill. 



Of Bulimus Uquabilis and confinis I have given the original description and a 

 fac-simile of the original figures in the fourth volume of the Terrestrial Mol- 

 lusks. 



The jaw of Bulimulus dealbatus \s narrow, strongly arched, with distant, very 

 delicate anterior ribs, denticulating the concave margin. (See above, Fig. 269.) 



The lingual membrane consists of 94 rows of teeth, 25 — 1 — 25 teeth. (See 

 above, p. 387.) 



The anatomy is figured by Leidy (1. a). The penis sac is very long; its 

 upper portion is narrow and very tortuous, and flagellate in appearance ; 

 although the true flagellum, or the free portion of the summit of the penis 

 beyond the insertion of the retractor muscle, is very short. The lower third of 

 the penis is dilated, and presents an annular constriction ; at its base it is 

 enveloped by a short prepuce. The vas deferens follows the course of the 

 penis nearly to its summit. The genital bladder is oval ; its duct as long as the 

 oviduct. 



Bulimulus serperastrus, Say. 



Vol. III. PI. L. Fig. 2. 

 Shell elongate, ovate, even fusiform, thin, with delicate lines of increment, 

 yellowish-white, with about 6 unecpial, interrupted, sometimes coalescent, 

 bluish-black bands on the large whorl, three of which are continued on the 

 upper whorls ; whorls 6 or 7, slightly convex, with a fine, well-marked suture ; 

 aperture less than half the length of the shell, lunate, one half longer than 

 wide, rather acute at base ; peristome sharp, expanded, its columellar portion 

 widening upwards, and protecting a moderate-sized umbilical opening ; colu- 

 mellar margin straight ; the bands of the exterior reappear, in still deeper 

 colors, in the fauces, but terminate at some distance short of the peristome, 

 which is white, or tinted more or less rose-color. Length 31, diameter 13 mill. ; 

 aperture 15 mill, long, 8 wide. 



Bulimus serperastrus, Say, New Harmony Diss., Dec. 30, 1830; Binney's ed., 

 39. _ Pfeiffer, Mon. Hel. Viv., II. 102 ; III. 341 ; in Chemnitz, ed. 2, 82, 

 PI. XXX. Fig. 122; PI. XXXIX. Fig. 5 (1854). — Philippi, Icon., III. 23, p. 

 43, Tab. IX. Fig. 6 (1850). —Reeve, Con. 'Icon., No. 252. — Binney, Terr. 

 Moll., II. 274, PI. L. Fig. 2. — W. G. Binney, Terr. Moll., IV. 126; L. & 

 Fr.-W. Sh., I. 192 (1869). 



Bulimus Liebmanni, Pfeiffer, Mon. Hel. Viv., II. 106. 



Bulimus Zicbmanni, Reeve, Con. Icon., 506. 



Bulimus nitelinus, Reeve, Con. Icon., 398. 



Drymceus serperastrus, Tryon, Am. Journ. Conch., III. 167 (1867). 



This species belongs more to the fauna of Mexico and Central America than 



