LIMNEANA. MOLLUSCA. LIMNiEA. 219 



Shell small and short-ovate, very thin and transparent, color a 

 light-olive, or sea-green ; whorls four or five, convexly rounded, 

 and somewhat shouldered or flattened above ; surface rather 

 coarsely marked by the lines of growth ; anterior whorl large and 

 inflated, two thirds the length of the shell ; posterior whorls small ; 

 suture deep ; aperture rather laige, somewhat more than half the 

 length of the shell, ovate, or nearly as broad behind as before, not 

 acutely rounded behind, but considerably arched ; slightly efi'use 

 at base ; columella arched, its fold conspicuous ; inner lip reflect- 

 ed over a small umbilicus, and the enamel usually broadly spread 

 across to the posterior angle. Length /^ inch, breadth ^^ inch, 

 divergence 68°. 



Lives along the muddy margins of brooks. 



The animal is of a dark sea-green or bottle-green color above, 

 dotted with amber-color ; beneath much paler. Foot long, and 

 inclining to a point behind. Li the region of the eyes, between 

 the tentacula, are clusters of white points, which give an appear- 

 ance of white eyes. The animal seems to shun immersion, being 

 usually found on the damp mud at the margins of ponds and 

 brooks. When put in a vessel of water, it soon rises above the 

 surface, crawls about the table, and will remain out of water two or 

 three days without injury. The shell is usually thickly coated 

 with mud. 



This species is distinguished from the young of L. elodes by the 

 depth of the suture, and the maturity of its aperture, which is also pro- 

 portionally larger. It is less elongated than L. desididsa, its suture is 

 deeper, its aperture rather smaller, and the color is quite different. 



Limn^e'a desidiosa. 



Shell ovate-elongate^ turretted ; schorls five, convcoL\ the upper 

 ones very small ; suture deep ; aperture siib-ovaie, longer than the 

 spire ; sub-umbilicated. 



Figure IHO. 



State Coll., No. 70. Soc. Cab., No. 1295. 



Lymncus desidiosus, Say ; Journ. Acad. Nat. Sc, ii. 1G9. 

 Liiniieus desidiosus, Say ; Amcr. Conrli., pi. 55, f. 3. 



