Bulletin 47, United States National Museum. 



south to Cape Cod. Not abundant in America. "Intrat et devorat 

 Pisces; aquam in gluten mutat." (Linnaeus). (Eu. ) 



Myxine glutinosa, LINN^US, Syst. Nat., Ed. x, 650, 1758, Atlantic Ocean; GATHER, Cat.,vui, 



510, 1870; PUTNAM, Proc. Bost. Soc. Jfat. Hist., 1873, 135. 

 Myxinelimosa, GIRARD, Proc. Ac. Nat. Sci. Phila., 1858, 223, Grand Menan, Bay of Fundy; 



JORDAN & GILBERT, Synopsis, 5, 1883. 

 Gastrobrancfiuscoecus, BLOCK, Ichth., xn, pi. 413, 66, 1795, Denmark, etc. 



Order C. HYPEROARTII.* 

 (THE LAMPREYS.) 



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

 equivalent to the single family Petromyzonidw. (vTrepua, palate; uprto?, 

 complete; *. c., entire.) (PETROMYZONTID.E, Giinther, Cat., vin, 499-509.) 



Family IV. PETROMYZONID^E. 

 (THE LAMPREYS.) 



Body eel-shaped, subcylindrical anteriorly, compressed behind ; the 

 mouth nearly circular, suctorial, usually armed^vith horny teeth, or tooth- 

 like tubercles which are simple or multicuspid, resting on papillae ; those 

 immediately above and those immediately below the (Esophagus more or 

 less specialized ; eyes developed in the adult ; gill openings 7, arranged in a 

 row along the sides of the " chest ; " nostril on top of the head just in front 

 of the eyes; lips present, usually fringed; dorsal fin more or less deeply 

 divided by a notch ; the posterior 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 tooth- 

 less and have the eyes rudimentary. Separate generic names (Ammocoetes, 

 Scolecosoma, CHlopterus} had been applied to these larval forms, before it 

 was discovered that they were the normal young of the true lampreys. 



Genera about 7; species about 15; of the rivers of temperate regions. 

 They attach themselves to fishes and feed by scraping off the flesh with 

 their rasp-like teeth. Most of them ascend rivers or brooks at the spawn- 

 ing season, after which very many of the individuals die. (PETROMYZON- 

 TID^C, Giinther, Cat., vm, 499-509.) 



a. Second dorsal continuous with caudal. 



b. Supraoral lamina ("maxillary ") and infraoral lamina (" mandible ") destitute of teeth, 

 "the armature of the lamprey type being obsolescent;" otherwise as in Petromy- 

 zon ; sea lampreys. BATHYMYZON, 5. 



bb. Supraoral and infraoral laminae with teeth or tooth-like tubercles. 



o. Supraoral lamina contracted, the armature consisting of 2 or 3 cusps placed close 

 together ; discal teeth numerous, in concentric series ; anterior lingual teeth 

 with a median depression or groove ; buccal disk large in the adult, con- 

 tracted in the young. 



Anterior lingual tooth with a deep median groove and terminating in an in- 

 curved point ; dorsal fin divided. Large lampreys; anadromoue. 



PETROMYZON, 6. 



* For a detailed account of the North American Lampreys, see Jordan & Fordice, Ann. N. Y. 

 Ac. Sci., 1886. For an excellent account of the life history of certain species see Gage, in Wilder 

 Quarter-Century Book, 1893, pp. 420-479. 



