348 LAJVIPREYS. 



ORDEK GG.-HYPEROABTTA. 



{The Liimpreys?) 



FAMILY CXVI.— PETROM YZONTID.E. 



{J'Ue 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 papilla3. Eggi^ 

 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 olf the flesh, by means of 

 their rasp-like teeth. 



The American species are still very imperfectly known. 

 Until quite recently the lurvte were considered as form- 

 ing distinct genera, which have been termed ^-i??imoc(etes, 

 IScolecosoina^ Chilopterus^ etc. 



* Maxillary teeth close together, not forming a crescentic plate. 

 f Dorsals well separated. . . . PetromyzDn, 1. 

 ff Dorsals connected Ichthyomyzon, 2. 



** Maxillary tooth forming a crescentic plate, with a cusp at each 

 end; dorsal continuous Ammoccetes, 3. 



/. PETROMYZON, Linnreus. LAMniEYS. 



1. P. marinus, L. Gkeat Sea Lamprey. Resembles 

 the next, but larger, with a shorter head, which is l)ut 

 little longer than the "chest" (space occupied by the 

 branchial openings); color olive l)rown, mottled with 

 black; T^. 30 to 40. Marine, ascending rivers, eastward. 

 {P. amer'icanus^ LeS.) 



