306 



L WER IN VER TEBRA TES. 



The Auriculidie are mostly found in the neighborhood of the sea, especially in salt 

 marshes. The genus Auricula, from which the family derives its name, has but a very 

 remote resemblance to an ear ; the species are all inhabitants of 

 brackish-water swamps in tropical regions, and are characterized 

 by an absence of teeth on the outer lip of the long and narrow 

 aperture. In Scarabus the shell is laterally compressed, so that 

 the edges are angular; the ajjerture would be large were it not for 

 the teeth which arise from both lips, and the spire of the shell is 

 acute. The species all come from the tropical parts of the eastern 

 hemisphere, where they live in the woods near the shore. 



Alexia is represented in the United States by a single s]iecies, 

 A. tnyosotis, which does not extend farther south than New Jersey. 

 In Europe it is found on the shores of the Atlantic and the Medi- 

 terranean. It frequents places where it is covered by the tide for 



several hours each day, moving in 

 a very sluggish manner. Fresh 

 water kills it. Other species are 

 found in Europe and the West 

 Indies. The shell is of a general 

 dark horn color and bears two 

 tooth-like folds on the columella. 

 Canjchium is much like Pupa in 

 shape, and our single species, C. ex- 

 igtncm, is widely distributed under "^ 

 stones and moss in damj) places, 

 and is the only member of the 



family which in the United States is found far from the sea. 

 ^ In the s]jecies of 3felampus the shell is ovate in outline, the spire 



short, and the outer lip acute. Four species are found in the United 

 States, one on the Pacific and three on the Atlantic coasts. One of 

 the southern forms has received the specific name coffea, from its re- 

 semblance in size, shape, and color to a kernel of coffee. This species and an- 

 other, M. flavus, occur in the United States only in Florida, exce]it 

 when introduced elsewhere by means of vessels trading with southern 

 and West Indian ])orts. The remaining species, M. bidentatns, is com- 

 mon in the grass of every salt marsh from Massachusetts to Texas. 

 When young, this is a very pretty species, being brownish in color, 

 marked with revolving reddish bands, and the whole highly polished ; 

 but the adults are dirty and eroded. The length of a large specimen is 

 about h.alf an inch. 



■A The species of Cassidula have a subquadrate body whorl and very 



i\]\ short spire ; and the outer and inner lips are toothed. The species all 



J^yj belong to the Indo-Pacifie region, frequenting mangrove swamps and 



rocky shores. The species of Pedipes are all ti'opical and sub-trojiical. 



They have a looping gait like that of a measuring worm, and with this 



jieculiarity in locomotion is correllated a transverse groove on the foot. 



The members of the genus are among the most active of molluscs. No species occur 



in the United States, the nearest approach being Lower California, where P. lirata 



Fig. 351. — A 

 exia myosot 



Fig. 352. — Cary- 

 chium ex'tguum. 



Fig. 353. — Me 

 tampus b'uhn 



