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ites, have been reported. The large number of troglobitesindicates that additional discoveries of interestawait study. The only aquatic troglobite known fromthe region is the bogidiellid amphipod Bogidiella sp.ef. vomeroi Ruffo and Vigna Taglianti. Bogidiellavomeroi is known from the Simojovel and Tila region.The terrestrial troglobites are the opilionid Hoplabunuszullinii Silhavy, the trichopolydesmid millipedsCaramba grandeza Shear and Tylogoneus sp.,and the leiodid beetle Ptomaphagus (Adelops) sp.The troglophiles are the pyrgodesmid millipedsMyrmecodesmus inornatus Shear and Synopturazullinii (Shear) and the sphaeriodesmid millipedSphaeriodesmus trullatus Shear. The genus Carambais known only from caves in Chiapas; otherwise thefauna is typical of that of southern and easternMexico.Palenque. Chiapas.-This is a poorly definedregion located south of Palenque and includingSaito de Agua. The only cave so far visited is Cuevadel Salta de Agua, a large seasonal resurgence locatednear the town of Salta de Agua. Two species, anundetermined rhachodesmid milliped and an ant ofthe genusPachycondyla, have been identified.Rancho del Cielito, Chiapas.-This region is locatednear the village of Colonia Galeana in westernChiapas. The only caves studied in the area are Cuevade las Canicas at an elevation of 1.350 meters andCueva del Cerro Brujo at 1,320 meters. The first caveis a 20-meter-deep sinkhole leading to a small passage;the latter cave is complex and only partially ex plored.Both caves are described by Sbordoni et al. (1974).The fauna of this region remains poorly studiedand only seven species, of which three are troglobites,have been reported. The troglobites are the trichoniscidisopod Brackenridgia sp., the bogidiellid amphipodBogidiella sbordonii Ruffo and Vigna Taglianti,and the ricinuleid Cryptocellus sbordonii Brignoli.All are typical elements of the Chiapas fauna. Thetroglophiles are the mysmenid spider lHaymenasbordonii Brignoli and the nesticid spider Eidmannellapallida (Emerton). Maymena sbordonii isknown only from this region, while E. pallida is awidespread species throughout North America.San Cristobal de las Casas, Chiapas.~ This region,located on the plateau-like Sierra de San Cristobal,extends from San Cristobal de las Casas to the vicinityof Comitan de Dominguez. Karst developmentis considerable and includes areas of dolinas withlittle relief. Other areas, however, contain tlle greatestdevelopment of karst in North America, with hugesinkholes, sinking streams, poljes, and pinnacles. Thegeology along the highway from San Cristobal de lasCasas to Comitan de Dominguez is discussed byGutierrez Gil (1956). The caves, many of which aredescribed by Sbordoni et al. (1974, 1977), areprobably formed in the Sierra Madre Limestone andoccur at elevations from 1,820 to 2,520 meters. Thecaves range from shallow pits with minimal horizontalex tent to large horizontal caves and stream systems.Grutas de Rancho Nuevo is located about 10 kilometersfrom San Cristobal de las Casas on the highwayto Comitan de Dominguez and is an extensive horizontalsystem with more than two kilometers of surveyedpassage (Thompson, 1972). Several major cavesare known in the vicinity of Huixtan. The largest ofthese is Sumidero Yochib with a depth of 213 metersand a surveyed length of 3,316 meters (Van Note,1977). Sumidero Yochib contains one of the largerunderground streams in Mexico and is very dangerous.Other major stream caves in the Huixtan area areCueva Mapachero and Salida de Cruz Pilal.The San Cristobal de las Casas region is one of thebetter studied in Chiapas with respect to its invertebratecave fauna despite the fact that much of thematerial collected by the Italian biospeleologistsremains unstudied. The 38 investigated caves contain53 identified species, of which 14 are troglobites.The aquatic fauna is particularly interesting and includesseven troglobites: the dimarcusid flatwormOpisthobursa josephinae Benazzi; the dugesiid flatwormDugesia mckenziei Mitchell and Kawakatsu; theasellid isopod Caecidotea chiapas Bowman; the bogidiellidamphipods Bogidiella orchestipes Ruffo andVigna Taglianti, B. sbordonii Ruffo and Vigna Taglianti,and B. tabascensis Villalobos; and the crabTyphlopseudothelphusa mocinoi Rioja. With theexception of B. tabascensis (known also from Grutasdel Cocona, Tabasco) and T. mocinoi (known alsofrom the Comitan de Dominguez region) all of thesespecies are endemic to this region. The terrestrialtroglobites are an undescribed species of schizomid ofthe genus Schizomus, the opilionid Troglostygnopsisanophthalma Silhavy, a glomerid milliped of thegenus Glomeroides, the cleidogonid milliped CleidogonaJelipiana Shear, a collembolan of the subfamilyParonellinae, and the carabid beetle Chiapadytesbolivari Vigna Taglianti. The last species is the onlytroglobitic trechine beetle in Chiapas and is endemicto this region.The only aquatic troglophile in the region is theubiquitous amphipod Hyalella azteca (Saussure).Terrestrial troglophiles of interest are the agelenidspider Tegenaria florea Brignoli; the leptonetidspider Archoleptoneta arganoi (Brignoli); the nesticidspiders Eidrnannella pallida (Emerton) and Gaucelmuscalidus Gertsch; the pholcid spiders Coryssocnemispecki Gertsch, Modisimus propinquus O. P.-49