330 



LOWER VERTEBRATES. 



skulls, and cartilaginous sterna. Of those with complete skulls, but a few (genus 

 JOeptodactylus, etc.) have an osseous sternum. The species of the Australian genus 

 Eeleioporus resemble toads. On the other hand, the species of Leptodactyhcs, and 

 still more those of Pseudis, resemble frogs. Many of the Hylodes resemble tree- 

 toads. Several of the species of JLeptodactylus (a genus which ranges from Patagonia 

 to northern Mexico) possess remarkable horny excrescences for the pui-pose of 

 maintaining a firm hold of the female during copulation. There is in L. pentadactylus 

 a process of the metacarpal bone of the thumb, which is directed inwards, and is 

 capped with horn. On each side of the breast is a horny shield, which terminates in 

 three sharp points. The CystignatJms ocellatus is the largest species of the family. 



Fig. 197. — Chorophllus onuitus. 



nearly equalling the Hufo marinits in dimensions. The humerus of the male has 

 a high deltoid crest, and in the breeding season the muscles of the arm of the male 

 become greatly developed. 



The species of Lithodytes inhabit rocky regions. They are especially abundant 

 north of the Isthmus of Panama. One species, L. latrans, is found in western Texas. 

 It lives in the fissures in the limestone precipices, and is supposed to deposit its eggs 

 in pools of rain-water, which are caught in caverns and holes. At such times its loud 

 voice issuing from the rocks is a cause of much speculation to the people, who cannot 

 detect its source. They usually ascribe it to a species of lizard (genus Gerrhonotus). 



Species of Hylodes occur in all parts of tropical America. The S. martinicensis 

 is one of the most abundant frogs of the West Indian islands. Although furnished 

 with digital dilatations, it lives on the ground, concealing itself in pairs beneath 

 various objects. On the approach of rain it is very noisy, and its cry is supposed by 

 the negroes to be uttered by lizards which they see in the same localities. The 

 curious fact has been observed in Guadaloupe by Bavay, and by Bello and Gundlach 



