1922.] 



S. L. Hora: Fish o) Mountain Torrents. 



45 



on the chest between the bases of the pectoral fins and lastly on 

 the under surface of the pectoral and pelvic spines, and I have been 

 able to make out a series showing the gradual specialization of the 

 adhesive apparatus in the Silurid genera. 



The genus Eicthistes comprises small hill-stream forms in 

 which the under surface of the body is smooth and greatly flat- 

 tened. In one member of the genus, E. elongata, the structure is, 

 however, somewhat different. The whole of the chest and the belly 

 (fig. 7, b) is rugose and shows low, but well-marked striations. 

 In the forms which I have assigned to my new genus Laguvia, these 

 corrugations are restricted to the chest and the belly is quite 

 smooth (fig. J, a). This feature is still further marked in the 



TexT-PIG. 7. — Under surface of head and chest of Laguvia sp. and 

 Erethistes elongata. 



a. Laguvia sp. b. Erethistes elongata. 



members of the genus Glyptothorax, where a definite U-shaped or 

 V-shaped adhesive apparatus consisting of folds of skin is present 

 on the chest between the bases of the pectoral fins. In certain 

 species of the last genus from very rapid waters an adhesive ap- 

 paratus of a similar nature is also present on the under surface 

 of the pectoral and pelvic spines. In Pseudecheneis sulcatus the 

 skin is somewhat differently modified on the chest, but the stria- 

 tions on the spines of the paired fins are of a similar nature to 

 those of the preceding genus. 



Specialization has proceeded along another direction in the 

 genus Glyptosternum. Here the skin on the under surface of the 

 spines (figs. 8a and c) is striated and each ridge is supported by 

 a short, pointed, cartilaginous ray given off from the outer side 



