MAMMALS OF THE MEXICAN BOUNDARY. 



77 



{Elaps f'ulvius) and rattlesnakes {Crotalus adamanteus atrox"-') are 

 abundant ; and numerous other species were collected. 



TJio, following is a list of the land and fresh-water mollusks collected 

 in the vicinity of Fort Clark, Texas : * 



1. Polygyra texasiana Moricand. 



2. Limax caiiipestris Binney. 



3. BuUmnlus dealbatus Say. 



4. BuJimulus dealiatus ragsdalei 



Pilsbry. 



5. Bulimulus alternatus marke Al- 



bers. 



6. Glandina texasiana I'feifEer. 



7. Pupa fallax Say. 



8. Pupa contracta Say. 



9. Succinea Uneata W. G. Binney. 



10. Succinea avara Say. 



11. Succinea luteola Gould. 



12. Heliclna orbiculata Say. 



13. Zonitoides radiatula Alder. 



14. Limnwa columella Say. 



15. Limnwa humilis Say. 



16. Physa osculans Haldeman. 



17. Planorbis Uehmanni Dunker. 



18. Pla^norMs tumidus PfeifEer. 



19. PlanorMs trivolvis Say. 



20. Planorhis ticarinatus Say. 



21. Valvata guatemalensis Morelet. 



22. Amnicola peracuta Walker. 



23. Amnicola sp. 



24. Sphwrium elevatum Haldeman. 



25. Sphmrium solidulum Prime. 



26. Pisidium compressum Prime 



27. Lampsilis anodontoides Lea. 



28. Lampsilis texasensis Lea. 



29. Lampsilis texasensis compressus 



•Simpson. 



30. Lampsilis berlandieri Lea. 



31. Lampsilis mearnsi Simpson. 



32. Anodonta imbecillis Say. 



33. Vnio popeii Lea. 



34. Quadrula undulata Barnes. 



35. Quadrula couchiana Lea. 



Station No. 3. — Fort Hancock, El Paso County, Texas. Altitude, 

 760 meters (2,500 feet). Post built on bottom land beside the Rio 

 Grande. Lines of cottonwood and willow mark the shifting 

 courses of the river, which dries up at certain seasons. The river 

 fiats are occupied by dense patches of arrowwood, flanked by the 

 tornillo or screwbean and mesquite. Still farther back is an arid 

 waste of sandhills and desert country, forming one of the lower basins 

 of the Eastern Desert Tract, with the characteristic desert flora in 

 which the KcBherlinia and a coarse Senecio are conspicuous. 



This region- is sparsely inhabited, not irrigated, nor under culti- 

 vation. 



This important station was occupied by me from June 7 to July 2, 

 1893. Large collections of animals and plants were made. The 

 birds and mammals were of special interest, particularly the former, 

 as thej' were almost all breeding specimens, frequently taken with 

 their nests and eggs, and all typical of the Eastern Desert. 



oFor convenience the determinations and nomenclature of Edward D. Cope 

 in the work entitled The Crocodilians, Lizards, and Snakes of North America, 

 printed In the Report of the U. S. National Museum for 1898, are here adopted. 



* The greater part of these were collected after the publication of Dr. Wil- 

 liam Healey Dall's report on the mollusks collected by the Biological Section 

 of the International Boundary Commission, printed in the Proceedings of the 

 United States National Museum, XIX, 1896. I am. indebted to Doctor Dall and 

 Mr, Charles Tprrey Simpson fgr assistange in detertaining these species, 



