URODELA. 305 



for a considerable time. The development is almost always 

 partly embryonic and partly larval, but in a few viviparous 

 forms the young are born fully developed. The larva has gills 

 and gill-slits which may or may not persist in the adult. They 

 are mostly aquatic animals, but a few leave the water and are 

 purely terrestrial in the adult state, merely returning to the 

 water to lay their eggs or deposit their larvae. They are car- 

 nivorous and live on insects and worms and such like. In a 

 few cases the larvae have the power of developing sexual organs 

 and of reproducing (paedogenesis, neoteny). This frequently 

 hapjDens in the genus Amhlystoma and occasionally in other 

 genera {Triton). They are found all over the temperate parts 

 of the northern hemisphere but do not {Spelerpes excepted) 

 extend into the southern. There are about 100 species. 



Fam. 1. Amphiumidae. Without gills in the adult ; gill-clefts absent 

 or one pair only (between the third and fovirth branchial arches) ; with 

 maxillary bones ; both jaws with teeth ; vertebrae amphicoelous ; two 

 pairs of small limbs ; without eyelids ; United States, E. Asia. Crypto- 

 branchus* Leuck., limbs functional with 4 fingers and 5 toes, gill-cleft on 

 both sides or on left side only. C. (Menopoma) alleghaniensis Daud., tho 

 hellbender, about 18 in., entirely aquatic, E. United States ; C. japonicus 

 v.d. Hoev., without gill-openings, in China and Japan 600 to 4500 ft. above 

 sea-level in small streams, may attain to 5 ft., eggs laid in Aug. and Sept. 

 in strings. Amphiuma Gard., N. America, gill-opening present, 4 branchial 

 arches, limbs very small, digits 2 or 3 ; .4. means Gard. to 3 ft., swamps 

 or muddy waters, eggs laid in Aug. and Sept., female coils round them. 



Fam. 2. Salamandridae.t Without gills or gill slits in the adult, 

 maxillary bones present, both ja.ws with teeth, with movable ej^elids 

 except in Typhlotriton, two pairs of limbs. 



Sub-fam. 1. Desmognathinae. Series of palatal teeth trans- 

 vei'se, restricted to posterior portion of vomers, parasphenoid with 

 dentigerous plates, vertebrae opisthocoelous, 5 toes, N. America ; 

 Desmognathus Baird, D. fuscus Raf., to .5 inches, Kmgless, eggs in 

 strings wrapped round the body of the female, said to be meroblastic ; 

 Thorius Cope, Th. pennatulus Cope, vmder two inches ; Typhlotriton, 

 blind. Rock HoLise Cave in Missoiu-i. 



Sub-fam. 2. Plethodontinae. Like the last except vertebrae 

 amphicoelous and 4 or 5 toes, confined to America except Spelerpes 

 fuscus, foimd in Evir. (mountains near Gulf of Genoa and Sardinia) ; 

 Spelerpes Raf., " tongue attached by its central pedicle only, is free 

 all round, ends in a soft knob, and can be shot out to a considerable 



* Hyrtl, Cryptobranchus japonicus, Wien, 1865. 



f Rusconi, Amours des Salamandres aquatiques, Milan, 1821. Id, 

 Hist, nat., development, et metamorphose de la Salamandre terrestre, 

 Paris, 1854. v. Siebold, Observationes quaedam de Salamandris et Tritoni- 

 bus, Berolini 1828. Id. Ueb. d. receptaculum seminis d. weiblichen 

 Urodelen, Z. /. iv. Z. 1858. 



Z— 11 X 



