342 BtiUefin 4y, United States National Museum. 



The species are few, but highly diversified in structure, constituting two 

 suborders and four families. They are probably related to the Apodes, but 

 this is not certain, and in the structure of the liead they approach more 

 nearly to the true fishes. They represent degraded rather than primitive 

 types, and the line of their descent is as yet unknown. It is not even 

 certain that the forms grouped in this order are closely related. Cope 

 makes two orders of them, Ichthi/occphaU, {Monopteridw), and Holostomi, 

 {Amphipnonhr of Gill, and Si/mhrauchidfr). But Dr. Gill has shown that the 

 Sjimhranchido' helong rather with the Monopterklw. {Symhrancliidw, Giin- 

 ther, Cat., VIII, 12-18,1870.) (fi5r, together; /V'}I««) giUs-) 



Analysis of Families of Symbranchia. 



a. Syniplcctic present. 



h. Shoulder girdle connected to the skull by a bony post-temporal ; vent behind the mid- 

 dle of the body ; vertebrae about 80 + 55 ; gills well developed ; palatine teeth in a 

 baud ; gills without peculiar modification. SYMBRANCHiD.ii:, xli. 



Family XLI. SYMBRANCHID^. 

 (The Symbranchoid Eels.) 

 Body eel-shaped, naked, the abdomen very long, longer than the tail; 

 shoulder girdle attached to the skull by a well-developed, bifurcate post- 

 temporal ; snout short; eyes small, anterior ; teeth small; palatine teeth 

 in a baud ; gills well developed ; gill openings confluent in a narrow slit ; 

 4 gill arches; no accessory breathing sac ; gill membranes free from the 

 isthmus. Fresh water fishes, 1 genus and 3 species known. (Symbran- 

 chidd', genuH. SymhrcDichiis, Giinther, Cat., viii, 15-17, 1870.) 



148 SYMBRANCHUS, Bloch. 



Siimbranchus, BlocH, Ichthyologia, ix, 87, 1795, (marmoratns). 

 Vnibravchnperiura, LACtpEnE, Hist. Nat. PoisiS., v, G58, 1803, (marmorahis) . 

 Ophisternon, McCLEi.LANn, Calcutta Journ. Nat. Hist., v, 197, 1845, (hentjaUnsis). 

 TetrabrancJms, Bleeker, Nat. Tyds. Ned. Ind., II, C9, 1862, [micrnphthalmus). 



Characters of the genus included above. Three species known, two 

 from India, and the following, (f f i', together ; jipayxoq, giU-) 



572. STMBRANCHITS MAUMORATUS, Bloch. 



Snout short, rounded or pointed ; eyes small, rather close to the end of 

 the snout. Gill opening narrow, not extending to theedgeof the ventral 

 surface, generally transverse, arched, frequently appearing as a longitu- 

 dinal slit unless drawn out. VertebnB 79 + 57. Color brownish, variously 

 marbled, sometimes immaculate. Tropical America, in streams from the 

 Amazon northward to southern Mexico and St. Lucia; generally abundant. 

 Recorded northward from Vera Cruz, Trinidad, St. Lucia, Lake Peten, 

 Huamuchal, Rio Chisoy, etc. 



Symhranchus mannoraliiK, Bloch, Ichthyologia, ix, 87, pi. 418, 1795 ; Gf nther. Cat., viii, 15, 1870. 

 Symhranchus immacvlaltis, Bloch, I. c. , pi. 419, fig. 1. 



Synhranchus transversal it, Bloch & Schneider, 524, 1801, Guinea, after Gronow. 

 Unihranchapertiiragrisea,marmorata, immacHlalu, and lineata, Lac^pede, Hist. Nat. Pass., v, 058, 



T>80:5, Surinam. 

 Synhrftw-hns fiiliijiiKisus, KAN7ANI, Nov. Ooinni. Ac. Sci. Inst. Bonon., iv, 75, i>late 11, fig. 1, 



1840, Brazil. 

 Miirieyiii Imubrmis, Gronow, Catalogue Fishes, 18, 18.54, Sea of Guinea. 

 Symbranchus rittatus, Castei,nai\ An. Amor. Sud., 84, pi. 44, fig. 3, 1855, Rio de Janeiro. 



