2i6 A NATURALIST IN THE GREAT LAKES REGION 



m 



Fig. 285. — Land snails: a, Circinaria concava; b, Hclicodiscus parallel us; 

 c, Omphalina fidiginosa; d, Polygyra tridcntata; e, Zonitoidcs arbor cus; f, Polygyra 

 monodon; g, Pyramidula altcrnata; h, Philomycus carolinensis (a slug) ; i, Pyrami- 

 dula solitaria; j, P. perspectiva; k, Succinea avara; I, S. ovalis; m, S. rctusa; 

 n, Cochlicopa lubrica; 0, Bifidaria armijera; p, Vertigo ovata; the last three much 

 enlarged, 



