68 INTRODUCTION. 



knew a species of Lophius which walked about 

 the house like a dog ; while the Doras costatus, by 

 the bony arms of its fins, assisted by the plates 

 under the belly, which work like those of serpents, 

 can march over land as fast as a man can leisurely 

 walk.* 



The body of fishes is lubricated by a slimy 

 fluid, prepared in a series of glands generally 

 placed near and about the fore parts, a beautiful 

 natural arrangement, to allow the fluid to be car- 

 ried backward ; or the same oflfice is performed in 

 a more mechanical manner by what is called the 

 lateral line, and which is in reality a canal on the 

 scales, which is cither continuous, and conveys 

 the lubricating fluid backwards from the head and 

 neck, or has a communication with a series of 

 glands laterally disposed. 



In the Skate there is a large serpentine vessel 

 which surrounds the mouth, runs between the skin 

 and the muscles at the sides of the five apertures 

 into the gills, and likewise surrounds the nostrils ; 

 then it passes from the under to the upper part of 

 the upper jaw, where it runs backwards as far as 

 the eyes. From the principal part of this duct, 

 in the under side or belly of the fish, there are not 

 above six or eight outlets ; but from the upper 



• Dr Hancock, Zool. Jour. 



