140 VERTEBRATA. PISCES. 



leaving their native element."* In our own personal 

 observations of these fishes, however, we cannot 

 help thinking, that we have now and then seen them 

 alter their course slightly, rising and sinking again 

 to avoid a wave. Usually, however, they shoot 

 along in nearly a straight line, skimming so little 

 above the surface, that we have often seen them 

 strike the side of a rising wave and go under. They 

 have much the appearance of white swallows, at a 

 distance, but, when near, they gleam like polished 

 silver, and their long fins resemble a transparent 

 film, invisible unless pretty close. They fly by 

 night as well as by day, being often found on a 

 vessel's deck in the morning. The flesh is not dis- 

 agreeable, but dry and somewhat insipid. 



FAM. III. SILURID.E. 



A group of fishes of remarkable, but repulsive, 

 form, distinguished by the rounded cat-like shape 

 of the head, the body destitute of true scales, and 

 the mouth furnished with fleshy beards or tentacles. 



Silurus.^ 



Besides the characters of the family given above, 

 the true Silures have the first ray of the pectorals 

 forming a strong and notched spine ; a formidable 



* Wand, in N. S. Wales, &c. 



t The Greek name of some Egyptian fish of this family. 



