622 BIOLOGY. 



Now, although much dispute prevails concerning the 

 division of Fishes which should be associated with the 

 Lampreys, yet it appears to me that no others but the 

 narrow-mouthed Fistularidae and Pipe-fishes can follow, 

 since they resemble them not only in their cartilaginous 

 bones, but in the structure also of their branchiae. They 

 will thus truly occupy the place of the second family. 

 Whether the narrow-mouthed Globe-fishes are likewise 

 to be united with them or to be set up as a third family, 

 may seem to be matter of doubt. I adopt the first 

 course, and arrange at present the wide-mouthed or 

 Frog-fishes and Shads in the third family. 



Fam. 1 . Infusorial Fishes, Lampreys. 



Body vermiform, naked, and slimy, without mem- 

 bral fins. Ex. Branchiostoma or Amphioxys, Myxine, 

 Petromyzon. 



In these Fishes the mouth is quite in front and round, 

 being without maxillae and adapted for the purposes of 

 suction ; only one nostril, but mostly several branchial 

 foramina, which lead to cysts provided with reticular 

 branchiae, but without opercula. 



The Branchiostomata are the smallest Fishes, not much 

 above V in length, almost devoid of head, yet with 

 traces of eyes and a nostril. The Myxinae crawl even 

 into the rectum of other Fishes, and live therein like 

 Entozoa. The river or lesser Lampreys stick in the 

 mud ; the Lampreys cling fast by suction to stones, and 

 do not draw the water in through the mouth, but through 

 the branchial foramina themselves, like the lower 

 animals. 



Fam,. 2. Polypary Fishes, Narrovi-moutlied. 



Body cartilaginous, mouth having maxillae, but 

 unusually narrow, only one branchial foramen with 

 immoveable operculum Fistularidae, Pipe-fishes and 

 Globe-fishes. 



In this family we still meet with species entirely 

 naked, but covered also with plates, scutes, nails, and 

 spines. The corymbiform or tufted branchiae of the 



