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Cambridge, and Pholcophora bispinosa Gertsch; thericinuleid Cryptocellus bolivari Gertsch; the pyrgodesmidmillipeds Myrmecodesmus fissus (Causey)and Synoptura tioticho (Shear); the sphaeriodesmidmillipeds Sphaeriodesmus cruzbelem Shear and S.zontehuitz Shear; the roach Aglaopteryx chiapasFisk; and the histerid beetle Anapleus wenzeli V0­mero. All of these species are typical representativesof the cavernicole fauna of eastern and southernMexico.Simojovel and Tila, Chiapas.-This region islocated in north-central Chiapas in the vicinity of thetowns of Simojovel and Tila. The eight caves studiedin the region are described by Sbordoni et aI. (1977)and are located at elevations of 810 to 1,790 meters.The caves are generally large and most contain eitherstanding or running water. Several remain largely unexploredand may prove to be quite extensive.Of the 17 identified species, four are troglobites.The aquatic fauna includes the asellid isopod Caecidoteazullinii Argano, the bogidiellid amphipod Bogidie/lavomeroi Ruffo and Vigna Taglianti, and the trichodactylidcrab Trichodactylus (Rodriguezia) mensabakCottarelli and Argano. The last species is theonly troglobite in the family Trichodactylidae. Thetwo crustaceans are known with certainty only fromthis region, but are closely related to species occurringelsewhere in Chiapas, Oaxaca, and Veracruz. Theonly terrestrial troglobite is the euryurid millipedPolylepiscus vomeroi Shear. This species is of specialinterest in that it is the only troglobite in the familyEuryuridae. The troglophile fauna includes the nesticidspider Gaucelmus calidus Gertsch and the pyrgodesmidmilliped Synoptura italolegata (Shear); bothare widespread in southern Mexico.Tuxua Gutierrez, Chiapas.-This region is locatedin the Chiapa Depression and includes caves in thevicinity of Tuxtla Gutierrez, Berriozabal, and Ocozocoautla.Most of the caves are described by Sbordoniet aI. (1974, 1977) and are located at elevationsranging from 460 to 950 meters. The region is characterizedby relatively low relief and numerous smallmesa-like hills. Gutierrez Gil (1956) and Olivas(1956) have discussed the geology of the region.Cretaceous and Eocene limestone crops out in thearea. The principal Cretaceous formations are theOcozocoautla and Sierra Madre Limestones, andmost of the caves probably are formed in one of theseformations. Cueva Cerro Hueco, a horizontal cavefrom which a stream emerges, may be formed in anunnamed Eocene limestone. Cave development inthe area is generally horizontal, although a few sink.holes up to 75 meters in depth are known. Many ofthe caves visited are small, but some are large and ofgreater interest. Hoyo de Don icho to the west ofOcozocoautla contains a stream passage severalhundred meters long at the bottom of a 20-meterdeepsinkhole. The largest cave in the area is Cuevadel Chorreadero. This is a major stream cave 345meters deep and with more than three kilometers ofsurveyed passage (Thompson, 1972; Shawcross et aI.,1974).The Tuxtla Gutierrez region is the best-studiedpart of Chiapas, with 81 species having been identifiedfrom the 22 investigated caves. The fauna, however,includes only one possible troglobite, an undescribedmilliped of the family Trichopolydesmidae.The aquatic fauna includes, in addition to severalspecies of nematode, the crayfish Procambarus(Austrocambarus) mirandai Villalobos and the catfishRhamdia guatemalensis GUnther. Both endemicand more widely distributed species are representedin the terrestrial troglophile fauna. The endemicspecies are the isopod Trichorhina vandeli Rioja; thepholcid spiders Coryssocnemis facetus Gertsch, Metagoniamcnatti Gertsch, and .Modisimus tzotzileBrignoli; the scytodid spider Loxosceles tehuanaGertsch; the opilionid Akdalima vomeroi Silhavy;the pyrgodesmid milliped Synoptura rodriguezi(Shear); the roach Pseudomops nigrimaculis Fisk;and the scydmaenid beetle Euconnus (illadagassoconus)arganoi Franz. Other troglophiles of interestare the schizomid Schizomus portoricensis (Chamberlin),the amblypygid Paraphrynus aztecus (Pocock),the mysmenid spider llrIaymena mayana(Chamberlin and Ivie), the nesticid spiders Eidmannellapal/ida (Emerton) and Gaucelmus calidusGertsch, the pholcid spiders Modisimus propinquusO. P.-Cambridge and Physocyclus globosus (Taczanowski),the opilionid Arganotus macrochelis (Goodnightand Goodnight), the pyrgodesmid millipedSynoptura italolegata (Shear), the carabid beetlePlatynus colibor Whitehead, and the leiodid beetleDissochaetus curtus Portevin. All of these species aretypical representatives of the fauna of southernMexico.Tapijulapa, Tabasco.-This region is located nearthe town of Tapijulapa in south-central Tabasco nearthe Chiapas border. The only cave studied in the areais Cueva del Azufre a few kilometers south of Tapijulapaat an altitude of 50 meters. The geology ofthis region has been examined by Salas and LopezRamos (1951) who report the presence of Cretaceouslimestone of the Guayal Formation in the area ofTapijulapa. A stream of sulphurous water flows fromthe cave, which is about 500 meters long and containsa large bat colony in one part.50