MAMMALS OF THE MEXICAN BOUNDARY. 



77, 



{Flaps fulvhis) and rattlesjiakes {CroUdus adamanteus atro.c'^) are 

 abundant; and numerous other species were collected. 



The following is a list of the land and fresh-water niollusks collected 

 in the vicinity of Fort Clark, Texas : '^ 



6. 



7. 



8. 



9. 

 10. 

 11. 

 12. 

 13. 

 14. 

 15. 

 IG. 

 17. 



PoUjuyiu te.rasiaua Moricaiul. 

 Liiuu.v cauipcstris Biniiey. 

 BuJiinnlus dcalhatiis Say. 

 Bulhiudu.s (IcaJbatii.s rmisdalci 



Pilshry. 

 BuliviitJiis (iltcrinitii.s nntrhr Al- 



bers. 

 Glandina fcxasiaiiu Pfeiffer. 

 Pupa fallax Say. 

 Pupa contracta Say. 

 Succiiicu lincata W. G. Biuney. 

 Siicciiica (I vara Say. 

 Sued lira hit cola Gould. 

 HeJicinu orhiculata Say. 

 Zoniioidcs radiaUila Alder. 

 Limnwa columella Say. 

 Lhnna'a huniiris Say. 

 Physa osculans Haldeiuan. 

 Planorhis liehmanni Dunker. 



IS. Planorhis tUDiidus Pfeiffer. 



19. Planorhis trivolvis Say. 



20. Planorhis hicarinatiis Say. 



21. Yalvata guatemalcnsis Morelet. 



22. Amnicola peracuta Walker. 



23. Amnicola sp. 



24. Sphwriiim elevatum Haldeman. 



25. Spliwriiim solidulum Prime. 



26. Pisidium com press um Prime 



27. Lampsilis anodontoidcs Lea. 



28. Lampsilis texasensis Lea. 



29. Lampsilis texasensis compressus 



Simpson. 



30. Lampsilis herlandicri Lea. 



31. Lampsilis mearnsi Simpson. 



32. Anodonta imheciUis Say. 



33. Unio popeii Lea. 



34. Quadrula undiilata 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 ])y dense patches of arrow wood, 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 Ko'herlinia and a coarse Senecio are conspicuous. 



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

 vation. 



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

 1803. Large collections of animals and plants were made. The 

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

 as they were almost all breeding specimens, frequently taken w4th 

 theii )iests and eggs, and all typical of the Eastern Desert. 



o For 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 Ball's report on the niollusks collected by the Biological Section 

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

 United States National :Mu>euni, XIX. 1896. I am indebted to Doctor Dall and 

 Mr, Charles Torrey Simpson for assistance iu determining these species, 



