VENTRAL FINS, 19 



with which they doubtless crawl on the bottom of the 

 sea, just as they are known to do when placed upon 

 land. The pectorals of the Malthe nasuta, as before 

 remarked (^fig. \.a), are rather paddles^ or cartilaginous 

 lobes^ than real fins ; the rays are numerous, but so close 

 together^ and the membrane which connects them so 

 tough and inextensible, that we feel fully persuaded they 

 are more used for walking than for swimming. 



(22.) Having just mentioned the processes of the 

 pectoral fins in the TriglidcB, we may here notice those 

 of the genus Polynemus, which are strikingly analogous 

 to_, although very different in structure from^ the digitated 

 processes of the former. The general form of these 

 fishes bears much resemblance to the grey mullet^ 

 while their serrated gill-covers show a relation to the 

 percoid families ; from both of these^ however^ they 

 are too distinct to be classed as a subordinate group ; 

 while the fact of these and the Triglidce being the only 

 genera possessing pectoral processes_, has induced us to 

 class them as the representatives of each other. In 

 Polynemus, these processes assume the form of slender, 

 setaceous, and articulated rays, varying in different spe- 

 cies from four to ten on each side, where they are inserted 

 a Mttle in advance of the pectoral, and are sometimes so 

 long, as in P. paradiseus, as to exceed the entire length 

 of the whole fish. Although this and several other spe- 

 cies are by no means uncommon in India, the use of 

 these processes remains to this day entirely unknown. 



(23.) The VENTRAL fins rank next to the pectoral, as 

 representing the hinder feet of four-footed animals, and 

 the legs of birds. That they are less necessary, however, 

 to the swimming motion of fishes, than either the dorsal 

 or caudal, may be presumed from the fact, that in the en- 

 tire order o^Apodes,or eels, these fins are totally wanting: 

 they are the smallest in size of all the others, but by no 

 means always so. In general they are less than the pecto- 

 rals, often of the same size, and very rarely, as in Gym,' 

 netrus and Zeus, considerably larger. Much diversity is 

 observable in their situation and form : hke the pectorals, 



c 2 



