SHELLS OF EUREKA SPRINGS, ARKANSAS. 527 



distasteful to water moUusks, and these are found in large numbers in certain 

 places. 



While a considerable volume of water flows from part of the springs, yet by 

 reason of the large amount of gravel in the beds of some of the streams, the water 

 disappears in a short distance, so that in the dry season these beds show no water. 

 This is true of West Leatherwood Creek especially, and in places where there are 

 springs giving a large volume of water, and possibly, in part at least, the same 

 water which disappeared higher up stream, again sinks out of sight within a few 

 rods from these springs. In this stream I found shells of two genera only, Physa 

 and Ancylus, the latter only above the highest point where the water sank into the 

 gravel. In June I found Ancylus iafdus, Say, quite large and but few in num- 

 bers ; six weeks later none were found of more than about half size, but these 

 were very abundant. At this same time those found in another stream were 

 somewhat larger than at the former time, while they were much darker in color. 

 In this latter stream the size was about the same as in the November preceding. 

 In the first mentioned stream Physa gyrina, Say, were found in large numbers; at 

 the highest point the shells were the finest, while further down, at Sycamore 

 Springs, they were badly eroded. In one of the branches of this stream Fhysa 

 heterostrophe, Say, of small size was found in June with very clear and clean shell, 

 while six weeks after they were of the same size but almost black. 



Leatherwood Creek, the stream from • the principal spring, not having so 

 much gravel in its bed, does not go dry. In one of its upper branches I found 

 the Ancylus before mentioned, and at the same place I found a single specimen 

 each of Pisidium abdilum, Hold, and Limncza numilis, Say, the latter a dead shell, 

 and the closest search did not discover any more of this species. Of the former, 

 however, after making a small sieve, I obtained hundreds in a short time. 



These were the only species found at the Springs, but in the White River, a 

 few miles away, in addition to the Unios, I found, Melantho decisa, var. Integra, 

 Sphcerium sulcatum Lamarck, Pisidium compressum, Prime, Planorbis bicarinatus, 

 Say, Physa heterostrophe, Say, and several species of Melanions, of which two were 

 Pleurocera and the others Goniobasis, they being found in great abundance. 



The land shells were not found in large numbers, but more of them were 

 rare species. During the dry weather the larger helices were found on the under- 

 side of the rocky ledges which extend on either^.side of the valleys and ravines. 

 Helix albolabris, Say, was comparatively abundant, and on the highest grounds 

 was smaller^ heavier and darker than those found lower down. On the higher 

 grounds were also found Helix thyroides, Say, Helix exoteta, Binn, and the fine, 

 rare Helix divesta, Gould; none of them being found except at the highest 

 points. Other rare species were Helix labrosa, Bland, H. Jacksonii, Bland, 

 and H dorfenilliana, Lea, variety, all of them being confined to the higher 

 grounds. The latter is the variety of which Binney says, "I am much inclined 

 to consider this a distinct species, but remark upon it, as I believe it is more 

 commonly found in cabinets under the name dorfenilliana than the shell de- 

 scribed by Lea." Helix Perspectiva, Say, was found in considerable numbers: 



