314 LAMPREYS. 



OEDEK Ga.-HTPEEOAETIA. 



(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 larvae were considered as form- 

 ing distinct genera, which have been termed Ammocoetes, 

 jScolecosoma^ CTiilopterus, etc. 



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

 with the caudal; "maxillary tooth bicuspid." 



PETROMYZON, 1. 



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

 tricuspid." ICHTHYOMYZON, 2. 



/. PETROMYZON, Linnasus. LAMPREYS. 



> AmmocceteS) Dumeril, (jLarvce.) 

 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 

 "chest" (space occupied by the branchial openings); 

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

 Marine, ascending rivers, eastward. 



