THE NAUTILUS. 81 



among the limestone ridges on the western slope. In the north- 

 ern part of the Black Hills in Lawrence County, in Spearfish 

 Canyon and about on the dividing line between the deciduous 

 and pine woods, I found Oreohelix cooperi very abundant on 

 Sept. 29, 1912. A light snow covered the higher elevations and 

 the snails had hibernated; however I soon located them under 

 leaves, brush-heaps and logs. I think this is the most eastern 

 locality that they have been found. You will notice several 

 species listed from the Black Hills that are identical with those 

 found in the Rocky Mountain region. Mr. Vanatta writes that 

 "it seems that some of the shells found in New Mexico run up 

 the mountains into Colorado, and to the Black Hills in South 

 Dakota." Of course the environments would be very similar. 

 In the eastern part of the State, the lakes or rather the nat- 

 ural ponds, or "sloughs" as they are locally called, seem to be 

 the natural habitat for some of the species of Lymnaea and 

 Planorbis. In Deuel County in the "Cotteau Hills" where 

 these "sloughs" are numerous and shallow and practically 

 grown up with vegetation, I have found them exceedingly 

 abundant and of large size. Many wildducks nest here, and 

 during migration others stop to feed, so that in season, hunting 

 is good. I remember one small " slough " in particular, in the 

 fall of 1916, that seemed literally full of Lymnaea. stagnalis and 

 Planorbis trivolvis, that we called " Spoonbill Slough " from the 

 fact that this variety of duck was always to be found there. 

 We seldom shot them, as better ducks were plentiful; but now 

 I often regret that I did not think enough of it at the time to 

 take a few and examine their "crops" to see if they were 

 feeding on the young of L. utagnalis, which were abundant. 

 It was also in this locality in 1908 that I found the dead speci- 

 mens of Segmentina christyi. No live ones were there at the 

 time, as the " slough " had been dry a year or two previous. 

 Nor could I find them at any other pond. This was the first 

 record for the United States, and as Mr. Bryant Walker says, 

 "They probably came from Canada by the duck route". 

 ( To be concluded. ) 



