6 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



3. £S. sfOMSi* Lockingtou. 



"Eleven gill openings on eacli side ; ten teetli in tlie anterior and nine 

 in tlie posterior series. Fifteen inches long." — [LocMngton.) Coast of 

 California ; not rare. 



(Lockingtou, Amer. Nat. Dec. 1878, 793.) 



Okder C.-HYPEROARTIA 



{The Lampreys.) 



Nasal duct a blind sac, not penetrating the palate. This order is 

 equivalent to the single family Pet romyzont idee. {uTzzpdja^ palate j apTioc;^ 

 complete J i. e., entire.) (Petrom^/^jowi^dte Giinther, 499-500.) 



Family III.— PETROMYZONTID^. 



[The Lampreys.) 



Body eel-shaped, naked, snhcylindrical ajiteriorly, compressed be- 

 hind ; month nearly circular, suctorial, armed with horny teeth, which 

 are simple or multicuspid, resting on i)apillte ; those immediately above 

 and those immediately below the opening of the oesoi)hagus more or 

 less specialized ; eyes present ; branchial openings seven, arranged in 

 a linear series along the sides of the " chest "j nostril on the top of the 

 head; lips present, usually fringed; dorsal fin more or less deeply di- 

 vided by a notch ; the i)osterior part commonly continuous with the anal 

 around the tail ; intestines with a spiral valve ; eggs small. 



These animals undergo a metamorphosis ; the young are usually 

 toothless and have the ej'es rudimentary. Such forms have, until lately, 

 been considered as forming separate genera, which have been termed 

 AmmocoeteSy Scolecoso7na, Ghilopterus, etc. 



Genera 5 or G; species 15 or 20; found in all waters in temperate 

 regions. They attach themselves to fishes and feed by scraping oft' the 

 flesh with their rasp-like teeth. Among our species, four groups, ap- 

 parently of generic value, may be recognized, but the characters in 



* This species may be identical with J3. pohjtrema Grd. from Chili, incorrectly do- 

 scribed in Proe. Ac. Nat. Sci. Phila. 1854, 199, and thus characterized by Putnam, 

 Proc. Bosl. Soc. Nat. Hist. 1873, KiO: 



" Head about one third of total length, and contained about 1^ times in the length of 

 the abdomen. Tail contained 7 to 8 times in total length. Base of ionfjue between ilxe 

 seventh or eighth pair of gills. Gills ten on each side. Length from 13 to 22 inches. 

 Habitat: Coast of Chiii." 



