68 THE NAUTILUS. 



with a mass of vegetation consisting of smart- weed, various species 

 of sedges, grasses and bushes. Near the water, on a zone of about 

 two inches wide, winch is permanently wet, may be found two minute 

 snails: Vertigo rugosula Sterki and V. ovata Say. On the tops of 

 old and large logs there is frequently a deposit of earth, which sup- 

 ports a colony of land shells. Among these may be found Polygyra 

 thyroides and its variety bucculenta, Polygyra monodon var. friersoni 

 Pilsbry. Rarely may be obtained Polygyra carolinensis Lea. 



Roaming about on the logs may be found colonies of Succinea of 

 a black color. That is to say, the animal itself is black, covered 

 with small golden-colored spots, making a handsome animal. These 

 Suc:ineas would be found here in untold numbers, probably, were it 

 not for two enemies who derive a considerable part of their living 

 from them. One of these enemies is the whole Heron 1'amily, and 

 the other is the frog family. Between the heron and frogs the Sue- 

 cineas have a poor chance. 



As before remarked, bunches of various sedges grow on these logs. 

 These sedges grow in bunches about two feet high and about one 

 foot in diameter. Hidden in these bunches, down near the roots, 

 may be found another species of Succinea. These are of a straw- 

 yellow color. Between these and the blacks are several points of 

 difference. The blacks live on the logs, the yellow ones live on the 

 tussocks of sedges. Here is a nut for the evolutionist. Is the straw- 

 colored snail colored like straw because it lives on straw ? or does it 

 live on straw because it is straw-colored? Another point is that the. 

 straw-colored snail (who is nearly always hidden in the bunches of 

 grass) is sweet tasted, or at any rate is not nauseous; while the 

 blacks who roam about considerably have quite a pronounced bitter 

 taste. Both of these snails have been called S. salleana, but being 

 sure that there were two species, they were submitted to Dr. H. A. 

 Pilsbry, with the result that the blacks are Succinea luteola Gid., 

 while the yellow fellows are Succinea salleana, Pfr. 



Out in the water, among the floating roots of the duck weeds, etc., 

 may be found Planorbis trivolvis S;iy, and a minute Limncea. This 

 Limncea is the only representative of its tribe thus far seen in North- 

 ern La. No specimen over one fourth of an inch long has ever been 

 secured. It is labelled L. caperata Say, but with a good deal of 

 doubt. 



More about this raft and its inhabitants could be written, but hot! 



