446 HELICID^. 



and seems not to have the power of directing its way in the water, 

 though it will generally float. 



The animal is larger than the shell ; its color pale, with minute 

 black points, which are asseml)lcd into stripes upon the neck, and 

 into squares, or bands, upon the sides ; the neck is granulate above ; 

 a black line passes each side on the neck, from the tip of the tentac- 

 ula, disappearing under the shell. The shell is so vitreous, that 

 all the markings of the animal and colors of the viscera arc seen 

 through it, as are also the circulating vessels branching across the 

 back, and the heart pulsating, and sending the fluids through them. 



Further particulars will be stated under S. obliqiia. 



Succinea avara. 



Fig. 127. 



Shell very thin, Avrinkled, yellowish, whorls three, rounded ; suture deep ; ap- 

 erture rounded, ovate, more than half as long as the shell. 



Succinea avara, Say, Long's Exped. ii. 260, pi. 15, fiij:. 6 (1822) ; Bixxey's cd. 32, pi. 

 74, fig. 6. — Gould, Inv. 196, fig. 127 (1841 ). — Adams, Vermont Moll. 156 (1842). 



— I)e Kay, N. Y. Moll. 54, pi. 4, fig. 55 (1843). — Pfeiffer, Symb. ii. 56; Mon. 

 Hel. Viv. ii. 525; in Chemnitz, 2d ed. 51, pi. 5, figs. 18-20 (1854). — Binney, 

 Terr. Moll. ii. 74, pi. 67 c, fig. 4. — W. G. Binney, Terr. Moll. iv. 35. — Morse, 

 Journ. Portl. Soc. i. 29, fig. 75 ; pi. 9, fig. 76 (1864) ; Am. Nat. i. 607, fig. 47 (18G8). 



— Tryon, Am. Journ. Conch, ii. 2.33, pi. 2, figs. 11, 12 (1866). 



Succinea Wardiana, Lea, Proc. Am. Pliil. Soc. 1841, ii. 31 ; Tr. ix. 3; Obs. iv. 3 (1844). 



— Pfeiffer, Mon. Hel. Viv. ii. 525. 



Siirciiwa vermeta, Say, teste Gould (see doubtful species). — Tryon, Am. Journ. Conch, 

 ii. 233, pi. 2, fig. 10 (1866). 



Shell rather small, very thin and fragile, of a deep straw color ; 

 surface irregularly wrinkled ; whorls about three and a half, well 

 rounded, and separated by a deep suture, the last whorl 

 composing the greater part of the shell, but not very broad ; 

 aperture in adult and elongated shells, about half as long as 

 the shell, but generally proportionally shorter, of a rounded 

 5. nvnra. fomi, tlic cui'vc of tlic outcr lip, where it joins the preced- 

 ing whorl, being so great as to render the aperture nearly 

 as broadly rounded behind as in front. Length, seven twentieths 

 of an inch ; breadth, five twentieths of an inch ; divergence, fifty- 

 six degrees. 



A larger form is also found. 



Found about the margins of muddy streams, or sheltered under 

 loose objects lying about moist places. From Fort Simpson on 



