CIIKLOXIA. 413 



Fain. 1. Chelydridae. Nuchal plate with long costiforni processes 

 underlying the marginals ; plastral bones nine ; tail long ; snout with 

 powerful hooked beak ; temporal region incompletely roofed over ; fingers 

 and toes webbed, with claws ; very fierce. Chelydra Schweige. N. Amer. 

 to Ecuador, the snapping turtle, edible. Macrocleminys Gray, alligator- 

 turtle, X. Amer. Both genera may leave the water. Platychelis A. Wag. 

 Upper Jur. 



Fam. 2. Dermatemydidae. Nuchal plate with costiform processes 

 underlying the marginals ; plastral bones 9 ; temporal fossa not roofed 

 over ; aquatic, shell to one foot ; Central Amer. Dermatemys Gray, 

 Staurotypus Wagl., Claudius Cope. 



Fam. 3. Cinosternidae. Nuchal plate as above, 8 plastral bones, 

 temporal region not roofed ; i\merica n. of Equator. CinQsternurn Spix. 



Fam. 4. Platystern.dae. Nuchal plate without costiform processes ; 

 plastral bones 9, temporal region roofed over ; Burma, Siani, S. China, 

 aquatic. Platysternum Gray. 



Fam. 5. Testudinidae. Nuchal plate without well-developed costiform 

 processes, 9 plastral bones, lateral temporal arch usually present, no 

 parieto-squamosal arch ; cosmopolitan except Australia and Papuasia ; 

 includes terrestrial and aquatic tortoises ; about 20 genera. Kaclniga 

 Gray, India and Burma ; Callagur Gray, Malay P., Borneo. Baiagur 

 Gray, Bengal, Burma, Malay P. ; Hardella Gray, N. India ; Morenia Gray, 

 N. India and Burma ; Chrysemys Gray, tei-rapins or water toi'toises, America 

 from Canada to Argentina, carapace flat, feet webbed, tail short ; lively 

 and shy ; larger species are eaten. Ocadia Gray, China ; Malacoclemmys 

 Gray, N. Amer. ; M. terrapin extensively eaten in the U.S., and bred in 

 terrapin farms. Damonia Gray, E. Indies, China, Japan ; Bellia Gray, 

 Siam, Burma, Malay P. and Arch. ; Clemmys Wagl., N.W. Afr., S. Eur., 

 S.W. Asia, China, Japan, N. Amer., aquatic. Emys Dum., Eur., N.W. 

 Afr., W. Asia, E. N. Amer. ; E. orbictdaris L. the European pond tortoise. 

 Gistudo Flem., N. Amer., a terrestrial tortoise but allied by its structure to 

 the water tortoises ; C. Carolina L., box-tortoise. Nicoria Gray, E. Indies, 

 C. and S. Amer. Cyclemys Bell, E. Indies, S. China. Geoemyda Gray, 

 Burma, Malay P. and Arch. Chaihassia Theobald, N.E. India. Cinixys 

 Bell, trop. Afr., posterior portion of carapace moveable. Pyxis Bell, 

 front lobe of plastron moveable, Madagascar. Homopus D. and B., S. and 

 W. Afr. Testudo L., plastron immoveable (except in T. ibera), since Oligo- 

 cene, herbivorous and frugivorous, occasionally taking worms, molluscs 

 and insects ; eggs hard shelled ; usually hibernate in ground or aestivate, 

 nearly 40 species, S. Eur., S. Asia, Africa, S. North Amer., S. Amer. ; T. 

 graeca the common Greek tortoise ; T. polyphetnus the gopher tortoise of 

 N. Amer. Some tortoises attain a large size, shell to 55 in. (Giinther, 

 Proc. Lin. Soc, 1898) in some oceanic islands, e.g. the Galapagos Islands. 

 Mascarenes, Aldabra, Sejchelles, etc., where they have recently been 

 largely exteriuinated ; they may attain to a great age, 1 50 years or more ; 

 at the present time indigenous land tortoises are known only on the S. 

 island of Aldabra, representatives of other species only lingering as intro- 

 duced pets on tropical islands and in Europe. 



Fam. 5. Chelonidae. Turtles. Nuchal plates without costiform 

 processes ; plastral bones nine ; temporal fossa completely roofed over ; 

 limbs paddle shaped, claws one or two ; marine, depositing' their eggs in 

 the sand of iinfrequented shores, cosmopolitan within the warmer zones. 

 Chelone Brong. Ch. midas L. the green edible tru^-tle, Atl., Ind., and Pac. 



