340 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Helix diodonta, Say, Long's Exped., II. 257, PL XV. Fig. 4 (1824) ; ed. Binney, 

 39, PL LXXIV. Fig. 4. — DeKay, N. Y. Moll., 34, PL II. Fig. 18. — Deshayes 

 in Fer., PI. LXIX. 1, Fig. 2. 



Helix Sayi, Binney, Bost. Journ. Nat. Hist., III. 379, PL XVI. (1840) ; Terr. 

 Moll., II. 180, PL XXIII. —Adams, Vermont Mollusca, 160 (1842). — W. G. 

 Binney, Terr. Moll., IV. 70 ; L. & Fr.-W. Sh., I. 153 (1869). — Pfeiffer, 

 Mon. Hel. Viv., I. 382 ; in Chemnitz, ed. 2, III. 419, Tab. CXLVIII. Figs. 

 13, 14. — Leidy, T. M. U. S., I. 256, PI. XL Figs. 1 - 4 (1851), anat. — Mrs. 

 Gray, Fig. Moll. An., PI. CXCIII. Fig. 10, from Bost. Joum., no descr. — 

 Deshayes in Fer., I. 79. — Reeve, Con. Icon., No. 679 (1852). — Mopse, 

 Amer. Nat, I. 98, Figs. 4, 5 (1867). — Gould and Binney, Inv. of Mass., ed. 

 2, 426 (1870). — Lewis, Am. Joum. Conch., VI. 191, PI. XIII. Figs. 5-7 

 (1871). 



Mesodon Sayii, Morse, Journ. Portl. Soc, I. 9, Fig. 9, PI. IV. Fig. 10 (1864). 



ijlostoma Sayii, Tryon, Am. Journ. Conch., III. 38 (1867). 



Northern and Interior Regions. From Canada East to Michigan, Maryland, 

 Kentucky, and Tennessee, — in the last locality greatly developed, a specimen 

 figured by Lewis (1. c), measuring 1.40 inches. 1 



Animal light reddish-brown, eye-peduncles and tentacles smoky, eyes black ; 

 head and neck cylindrical, foot narrow, terminating in an acute point; length 

 about twice the diameter of the shell. (See Bost. Journ. Nat. Hist., I. 

 PI. XVI.) 



On the 3d day of July, 1836, Dr. Binney discovered an individual of this 

 species in the act of laying its eggs in a damp place under a log. He trans- 

 ferred them with the animal to a tin box filled with wet moss. The eggs were 

 not much more than half as large as those of M. albolabris, Say ; they were 

 white, adhering together very slightly, flaccid, and apparently not entirely fllled 

 with fluid. During the succeeding night the number had increased to about 

 fifty, and in a few hours they became. full and distended. As the snail now 

 began to devour the eggs, he was obliged to remove it. On the 29th of July 

 all the eggs were hatched ; the young snails had 1^ whorls; the umbilicus was 

 open ; the head, eye-peduncles, and tentacles were bluish-black, and the other 

 parts whitish and semi-transparent. They immediately began to feed, and made 

 their first repast of the pellicle of the eggs from which they had just emerged. 

 They grew rapidly, and before the middle of October, when they went into 

 winter-quarters, they had increased their bulk four or five times beyond its 

 original measurement. 



Jaw as usual in the genus ; 15 ribs. (See next page.) 



The lingual membrane (PI. VIII. Fig. B) has 42—1—42 teeth, with about 



l " H. Chilhoweensis differs from typical Sayii in having a cubic capacity more than five 

 times as great, smaller or more rudimentary teeth, a wider development of the reflected 

 lip on the base, and in several other less important details. The greatest diameter of the 

 mo^t perfect shell before me is about 1.40 inches." — Lewis. See also Proc. Acad. Nat. 

 Sci. Phi'a., 1875, 334. 



