314 LAMPREYS. 



OEDEE GG.-HYPEEOAETIA. 



(The Lampreys.) 



FAMILY CXVL PETROMYZONTID^E. 



(The Lampreys.) 



Body eel-shaped, naked; dorsal and anal fins long and 

 low, usually continuous with the caudal; mouth suctorial, 

 armed with horny teeth which rest on papillae. Eggs 

 small. 



These animals undergo a metamorphosis; the young 

 are usually toothless, and have the eyes rudimentary. 

 Genera five or six, in temperate regions, found in all 

 waters. They attach themselves to fishes and other ani 

 mals, and feed by scraping off the flesh, by means of their 

 rasp-like teeth. 



The American species are still very imperfectly known. 

 Until quite recently the larvce were considered as form 

 ing distinct genera, which have been termed Ammocaetes, 

 jScolecosoma, Chilopterus, etc. 



* Dorsal fins two, nearly or quite distinct, the second continuous 

 with the caudal ; &quot; maxillary tooth bicuspid.&quot; 



PETROMYZON, 1. 



** Dorsal fin single, continuous with the caudal ; &quot; maxillary tooth 

 tricuspid.&quot; ..... ICHTHYOMYZON, 2. 



/. PETROMYZON, Linnaaus. LAMPREYS. 



&amp;gt; Ammoccetes, Dumeril, (Larvce.) 

 1. P. marinus, (L.) var. americanus, (LeS.) Wilder. 

 GREAT SEA LAMPREY. Resembles the next, but larger, 

 with a shorter head, which is but little longer than the 

 &quot;chest&quot; (space occupied by the branchial openings); 

 color olive brown, mottled with black; L. 30 to 40. 

 Marine, ascending rivers, eastward. 



