COLIMACEA. MOLLUSCA. AURICULA. 197 



Found about the margins of muddy streams, or sheltered under 

 loose objects lying about moist places. 



I have much hesitation in deciding upon a name for this shell. It 

 is quite different from any other species I am acquainted with. The 

 spire is longer, and acutely pointed, the body-whorl less developed, 

 and the aperture is shorter and more rounded ; but, although the suture 

 is deep, it is not so much so as to " give the whorls the appearance of 

 being almost separated from resting on each other," as Mr. Say re- 

 marks of S. vermeta. In this character, individuals differ very greatly. 

 Some specimens with unusually lax spires may have been used by Mr. 

 Say in drawing up his description. But the young shells present no 

 prominent spire, and a large, rounded aperture, agreeing precisely 

 with Mr. Say's description and figure of S. avdra ; and they are also 

 always coated with earth adhering to a glutinous matter on the sur- 

 face. It seems probable that the two should form one species ; 

 unless they do, I am at a loss under which name to place our shell, 

 as, considering specimens of all ages and forms, it will come under 

 one as well as the other. The name I have chosen is to be preferred, 

 because it is a legitimate Latin word, while the other is not. 



The animal has a dark head, and gives a dark color to the shell ; 

 the foot is very narrow, with a flesh-colored tint. 



GENUS AURfCULA, LAM. 



Shell oblong-ovate ; aperture long and narrow, rounded in front, 

 lips sharp or rejlexed, disunited posteriorly ; pillar having one or 

 more plaits. 



AURI'CULA BIDENTA'TA. 



Shell ovate-conical, grey or brownish horn-color ; spire short and 

 obtuse, aperture narrow, two folds on the pillar. 



FIGURE 130. 

 State Coll., No. 52. Soc. Cab., No. 941. 



Melampus bidentatus, SAY ; Journ. Acad. JV7U. Sc., ii. 245. 



Auricula cornea, DESUAYES ; Encyc. Mdth., Vers y ii. 90. LAM. ; An. sans Vtrt., 

 viii. 339. 



Shell ovate-conical, broadest at about the upper third, where 

 there is a faint angle, thin, translucent, of a brownish horn-color, 

 smooth and shining, often becoming eroded, wrinkled lengthwise, 

 with occasional broken revolving lines, very minute ; whorls five 



