THE NATURAL HISTORY SURVEY. 223 



853. Succinea retusa magister Pilsbry. 



Succinea retusa var. magister PILSBRY, The Nautilus, Vol. XI, p. 143, 



1898. 



Succinea retusa magister PILSBRY, The Nautilus, Vol. XII, p. 103, 1899. 

 Shell: Differing from retusa in being generally larger and 

 in the less developed spire and larger aperture. 



Length, 19.00; width, 9.50; aperture length, 14.00; width, 7.00 mill. 

 Animal: Similar to type. 

 Jaw and Radula: As in retusa. 

 Distribution: Northern Mississippi Valley. 

 Geological distribution : Pleistocene; Loess. 

 Habitat: Same as type. 



Remarks: The variety does not seem to be as common as 

 the type, although it is equally as widely distributed. 

 86. Succinea avara Say, pi. xxx, fig. 25. 



Succinea avara SAY, Long's Exped., Vol. II, p. 260, pi. xv, fig. 6, 1822. 

 Succinea vermeta SAY, New Harm. Diss., Vol. II, p. 230, 1829. (Variety. 

 Succinea wardiana LEA, Proc. Amer. Phil. Soc., Vol. II, p. 31, 1841. 

 Succinea alba CKLL, The Nautilus, Vol. VII, p. 43, 1893. (Albino.) 

 Succinea compacta CKLL, 1. c., p. 44, 1893. 

 Succinea major W. G. BINNEY, 1. c., p. 44, 1893. (Variety.) 



Shell: Elongate-ovate, thin and fragile, shining; surface 

 covered with minute lines of growth with here and there a line 

 raised into an elevated ridge, which are more pronounced on 

 the last whorl; color straw to greenish-horn, sometimes rosy; 

 whorls three, rapidly increasing, rounded, the last whorl a trifle 

 more than half the length of the whole shell; spire rather long, 

 acutely conic; sutures deeply impressed; aperture roundly 

 ovate, last whorl not much expanded, straight or slightly 

 oblique; peristome sharp, simple; columella simple, almost 

 straight; when young, the shell is frequently slightly hirsute. 

 Length, 11.75; diam., 7.00; aperture length, 7.00; diam., 4.50 mill. (8462).) 

 11.00; " 6.00; " " 6.50; " 4.00 " (10439.) 



Animal: Dirty white or yellowish-white in color, darker 

 on head, neck and eye-peduncles; head distinct; eye-peduncles 

 blunt, conical, of medium length, eyes black, situated as usual; 

 foot long and narrow, somewhat flesh-colored, 8.00 mill, long 

 and 1.50 mill. wide. In some specimens the body is almost 

 transparent. The heart is situated one-sixteenth of an inch 

 from the middle of the columella, to the left, and the pulsations 

 number one hundred and thirty and are quite regular. 



Jaw: Very strongly arched, the ends much attenuated 

 and bent downwards; convex margin with two strong swellings 



