eigenmann: fresh water fishes. 231 



SYNOPSIS OF THE FRESH-WATER FISHES OF 



PATAGONIA. 



Class I. MARSIPOBRANCHII. 



= Marsipobranchii Bonaparte, Nuovi Annali delle Sci. Nat. t. 2, 1838 ; 



Muller, Abhandl. K. Akad. Wiss. Berlin, 1844. 

 < Myzontes Agassiz, Contrib. to Nat. Hist, of U. S., I, 187, 1857. 

 = Dennopfen Co^c, Proc. Acad. Nat. Sci. Phila. 1868, 256. 

 = Cyclostonia Gegenbaur, Grundriss der vergl. Anat. 577, 1870. 

 = Cyclostomata '^Qkvc\-\\^\., Handb. der vergleich. Anat. 6, Aufl. 259, 1872. 

 = Marsipobranchiates Gill, Arrangement Fam. Fishes, IX, 25, 1872. 



Skeleton cartilaginous ; skull imperfectly developed, not separate from 

 the vertebral column ; no jaws, no limbs, no shoulder girdle, no innomi- 

 nates ; no branchial arches, gills in sacks, 6 or more ; nares single, median ; 

 mouth suctorial, subcircular ; no bulbus arteriosus ; alimentary canal 

 straight, simple, without coecal appendages or pancreas ; an abdominal 

 pore ; development with a metamorphosis. 



Order I. HYPEROARTII. 



^ Hyperoartia Muller, Abhandl. k. Akad. Wiss., Berlin, 1844. 



Eel-shaped ; nasal duct a blind sack, not penetrating the palate ; gill- 

 opening close behind the head, communicating with a common branchial 

 passage which opens into the pharynx ; intestines with a spiral valve. 



Family I. PETROMYZONIDyE. 



= Lampredini 'R2L^nt's,(\wt, Indice dTttilog. Siciliana, 1810. 



— Petfomyzonidce Bonaparte, Nuovi Annali delle Sci. Nat. II, 133, 1838 ; 



Jordan & Evermann, Bull. U. S. Nat. Mus. 47, 8, 1896. 

 = Petro7nyzoutid<x Girard, Expl. and Surv. for R. R. Route to Pacific 

 Ocean, X, Fishes, 376, 1858. 



General distribution : Temperate regions in both the northern and south- 

 ern hemispheres, anadromous or landlocked. 



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

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

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



