NOTES ON BATEACHTANS OF THE PARAGUAYAN CHACO. 307 



yellow. Most inconspicuous on a background of earth. It is 

 very agile and extremely shy. 



In damp waste places on the outskirts of Concepcion I 

 found it in great numbers, but very difficult to capture. 



The call is a shrill sharp " ping " kept up constantly until 

 approached, when it immediately ceases. The croaking of so 

 many of them at a time produces an almost continuous sound. 



Though only one specimen was secured, it was frequently 

 heard on both sides of the river. This is probably the young 

 form of L. bufonius, which grows to about the same size as 

 L. ocellatus. I never detected large individuals of this form 

 calling, and I am convinced that during the continuous calling 

 described above the individuals about were of the small form 

 almost entirely. 



It would appear, then, that either young forms have the 

 habit of calling to one another, or that there is a small and a 

 large variety. Lengua name Ukksaliapertikk. In Lengua 

 Uksaelia means a coin or disc. The name refers to the 

 spots. 



IV. Leptodactylus p(ecilochilus (Cope). 



This frog is much less common than L. ocellatus. It is 

 of a more slender build ; the toes are thin and long, especially 

 the second toe. The markings are all in the form of stripes 

 rather than spots. These are dark brown on a greyish-brown 

 ground. At the side yellowish. One broad dark stripe runs 

 down the back on either side at the edges of the transverse 

 processes of the vertebrae. One specimen was found at Con- 

 cepcion and one at Waikthlatingmayalwa. 



I do not know if it has a native name. 



V. Phryniscus NIGRICANS, Wiegm. 



This is a brilliantly coloured frog of toad-like appearance. 

 The ground colour is black, and is irregularly spotted with 



