332 BULLETIN 34, UNITED STATES NATIONAL MUSEUM, 



the former, the ethmoid plate without supraorbital angles, the elongate 

 terminal phalanges with small basal globe, supporting minute dila- 

 tations, and the nearly webless digits distinguish it. Species of Hyla 

 less representative are similar in cranial structure, and have a dimin- 

 ished amonnt of palmation, but the series appears with our present 

 knowledge distinct in the structure of the feet. Like the Litorias, its 

 life is passed on the ground, and chiefly in the neighborhood pf small 

 pools in open and barren situations, where the voices of the species 

 may be heard with the Acris in the summer, long after the Hylas have 

 sought their leafy retreats in the wood or fence row. Tliey ditfer from 

 the first-mentioned genus in being poor swimmers; though they leap 

 into the water when alarmed, they do not swim far from the shore, 

 and soon return to it. They do not seem to be possessed of the power 

 of making such enormous leaps as the Litorias of Australia, or even 

 as our Acris. In typical Litoria the brain case is more elongate and 

 cylindrical and the frontoparietal fontanelle much narrower, but in 

 L. amerkana the form and proportions are the same. 



The general form and habits of the Australian genus Crinia are not 

 very different from the present; the terminal, not inferior, attachment 

 of the ultimate phalanx will separate it from all flylidte. 



Chorophilus is distributed from the Eio Grande, Salt Lake Valley, 

 and Eocky Mountains on the west, to the Atlantic, and from the Gulf 

 to the northern limits of the Uuitecl States west of the Alleghanies; 

 east of this range lam not aware of its occurring north of middle 

 Pennsylvania. Of its six species four are confined to the Gulf States 

 and South Carolina, while the fifth is found under several forms 

 throughout the whole of the north and southwest, the northern and 

 middle parts of the central, and the middle of the eastern region to 

 Pennsylvania and New Jersey. 



The species differ as follows: 



I. Muzzle rounded in profile, projecting. 

 a. Skin of upper surfaces smooth. 



Stout, -widtli of head at tympana entering total length 2.5 to 2.66 times; 

 nostril half-way between muzzle and orbit; posterior foot shorter, slightly 

 webbed, and with subarticular tubercles ; heel reaching tympanum 

 C. ornatm. 



More slender ; width of head entering length 3 to 3.5 times; nostril nearer 

 end of mxizzle than orbit ; posterior foot longer, not webbed, and without 



subarticular tubercles ; heel reaching middle of orbit C. otcidentaJin. 



aa. Skin warty above. 



Head acuminate, the width entering the total three times; heel reaching 

 anterior to orbit ; size larger , . C. vir/ritiis 



Head short, wider; the width entering the length 3.25 times; the heel 

 reaches to the front of the orbit ; small C, feriarum. 



Head acuminate; the width entering the total 3.5 to 3.66 times; hind legs 

 short; heel reaching posterior border of membranum tympaui 

 C. triseriatus. 



II. Muzzle truncate in profile. 



Vertex and front plane ; cauthus rostralis sharp ; hind legs long. . C. ocularis. 



