CLASS PISCES. G19 



which they have on each side. The skin is raised, 

 above and under the tail, into a longitudinal crest, 

 which holds the place of a fin, but in which the rays 

 are only observed, as fibres scarcely sensible. 



Petromyzon, Dumeril. (Lampreys, properly so called) 



Their maxillary ring is armed with strong teeth ; and 

 tubercles, invested with a very hard shell, and similar 

 to teeth, furnish more or less the interior disk of the 

 lip, which is very circular. This ring is suspended 

 under a transverse plate, which appears to hold the 

 place of the intermaxillaries, and at the sides of which 

 we see some vestiges of the maxillaries. The tongue 

 has two longitudinal ranges of small teeth, and is car- 

 ried backward and forward like the sucker of a pump, 

 which serves the animal to perform the operation of 

 suction which distinguishes it. The water comes 

 from the mouth to the gills by a peculiar membranous 

 canal, situated under the oesophagus, and pierced 

 with lateral holes, which may be compared to a 

 trachea. There is a dorsal in front of the anus, and 

 another behind, which unites to that of the tail. 

 These fishes have the habit of fixing themselves by 

 suction to stones and other solid bodies ; by the same 

 means they attack the largest fishes, pierce and de- 

 vour them. 



think, from Lambendo petras. Petromyzon is the Greek translation 

 of this made by Artedi. It is singular that any uncertainty should 

 exist respecting the ancient name of a fish so much esteemed, 

 and so common in the Mediterranean. 



