RANDOM NOTES ON NATURAL HISTORY. 



63 



the others are distributed around on the 

 margin of the lip. 



Vertigo ovata, or Pupa niodesta as it was 

 formerly called, is the largest of our species 

 of this genus, being three-fortieths by one 

 twenty-fifth of an inch. It is found only 

 in wet places, under chips, leaves, stones, etc. 

 1 found once a large number of them at 

 Tawtucket, in a ledge of rotten slate. By 

 breaking off pieces of the slate, the shells 

 were seen between the layers of the stone. 

 It was close to a small pond and the stones 

 and shells were quite wet. 



113. "Vertigo (Al.ea) Simplex, Gould. 

 Described by Dr. A. A. Gould at the 



same time with V. milium as above. It is 

 a smooth, light chestnut colored shell, more 

 cylindrical in shape than the other species 

 of the genus ; apex blunt ; whorls five ; 

 length one-fifteenth of an inch, breadth one- 

 thirtieth. Its distinguishing character is its 

 circular aperture, destitute of teeth, and its 

 sharp lip. It is found in the woods under 

 leaves in Canada, New England, and New 

 York, Mr. Thomson finds it in damp places 

 in interstices of old logs in company with H. 

 electrina. 



1 14. Vertigo (Al^:a) Ventricosa, Morse. 



Described by E. S. Morse, A7in. N. Y. 

 Lye, VIII., 1 , 1865. Found in Maine, New 

 Hampshire, Massachusetts, Rhode Island, 

 and New York. 



Shell umbilicate, ovate-conic, light col- 

 ored, polished, apex obtuse ; suture deep ; 

 whorls four; lip widely reflected, the right 

 margin flexuose, within thickened and col- 

 ored. Length seven one-hundredths, breadth 

 forty-five one-thousandths of an inch. 



Family' Limacida>. Shell rudimentary 

 a calcareous plate, not spiral, concealed un- 

 der the mantle, and covering the respiratory 

 cavity. 



Famil3' Tebennophoridiae. Animal a 

 slug with neither external nor internal shell. 



Family Arionidae. Animal naked, with 

 mantle concealing a few calcareous grains 

 representing a shell plate. 



These three families all contain species 

 which inhabit Rhode Island, but are not 

 included in the shell-bearing moUusca. 



Family Succineidae, six genera, six sub- 

 genera and more than two hundred species, 

 is represented in America b}' the genus 

 Succinea ; this is divided into five sub- 



genera, of which two inhabit the United 

 States. These are, Succinea restricted, to 

 which Studer, 1830, gave the name of 

 Tapnda, and Brachyspira. Pfr., 1855. There 

 are about forty species in this country, four 

 of which inhabit Rhode Island. 



115. Succinea (Tai'ada) Avara, Say. 



This species was described by Say in the 

 appendix to Long's second expedition to 

 the St. Peter's River, 1822, as follows : 



" Shell sub-oval, pale reddish yellow, sub- 

 diaphanous, fragile, covered with an earthy 

 crust ; whorls three, minutely wrinkled ; 

 body whorl very large ; spire small ; aper- 

 ture sub-ovate,'^large, two-thirds the length 

 of the shell. Length three-twentieths of an 

 inch. Inhabits the Northwest Territory." 



Succinea avara is now catalogued from 

 nearly every state in the Union, east of the 

 Rocky Mountains. It is found about the 

 margins of muddy streams, and sheltered 

 under loose objects in moist places, but is 

 also found in Rhode Island, under leaves in 

 the woods far away from any water. 



The young shells have a large rounded 

 aperture, and scarcely any spire ; they are 

 always covered with a coating of dirt. 

 Under the glass they prove to be covered 

 with fine hairs which collect the dirt. As 

 they grow larger this peculiarity disappears 

 and the shells have a deep straw color. 

 Mr. Say's specimens evidently were not full 

 grown, as the size of the adults is seven- 

 twentieths of an inch, the aperture is one- 

 half the length of the shell and the spire is 

 quite long. 



Succinea (Tapada) Obliqua, Say. 



This is a large, in fact, the largest Amer- 

 ican species of Succinea. being one inch in 

 length, by three-quarters in breadth. It 

 has never" been quoted from New England 

 by any author, but Mr. Thomson in his 

 Land Mollnsca of Bristol County, says : '' S. 

 obliqua. Say, Tiverton, R. I. Very varia- 

 ble, but generally the typical form is found 

 in swaley" places on hillsides ; very nearly 

 allied to S. ovalis, GUI." S. obliqua does 

 «o« resemble S. ovalis, Gld., and I am in- 

 clined to think Mr. Thomson has mistaken 

 some large specimens of S. Totteniana, Lea 

 for the obliqua of Say. The next chapter 

 will contain descriptions of S. ovalis, Gould, 

 and of S. Totteniana, Lea. 



(To he continued.) 



