iJG8 CONTRIBUTIONS TO NOETII AMERICAN ICHTHYOLOGY IV. 



ORDER P.-OPISTIIOMI. 



(The A>/# Eds.) 



Scapular nrch suspended to the anterior vertebrre. Superior pliaryn- 

 geals and branchihyals ossified, the third pharyngcal a little larger, 

 the fourth small. Three basal branchihyals ; inferior pharyngeals 

 distinct; maxillary bone distinct; supraoccipital separating parietals; 

 no iutcrclaviclcs ; symplectic present; prrecoracoid wanting; parietals 

 separated by the supraoccipital; air-bladder, if present, without pneu- 

 matic duct; dorsal with spines; ventrals, if present, abdominal. The 

 fishes of this order differ from other Physodlaii and agree with the 

 Eels in having the scapular arch free from the cranium and attached 

 to the anterior vertebrce. Two families are known. (o-ir>0r n backward; 

 <jj;j.<>-, shoulder.) 



ANALYSIS OF FAMILIES OF OPISTHOMI. 



a. Ventral fins wanting; dorsal fin with the soft portion well develop*!. 



MASTACEMBELIRS, 5fi (/>). 



aa. Ventral fins abdominal, of numerous spines and soft rays; soft portion of the dor- 

 sal fin obsolete ......................................... NOTACA.XTIIID.K, 5C (<). 



FAMILY LVI (I). MASTACEMBELID.E. 

 (The Spiny Eclx.) 



Body elongate, eel-like, naked or covered with very small scales. 

 Moutli oblique, of moderate si/e, either the snout or the chin being 

 produced in a fleshy appendage ; lower jaw little movable; upper jaw 

 not protractile. Teeth small, dill-openings restricted to Hie region 

 belo\v the, convexity of the operculum, the upper part of the oper- 

 culum being covered by the skin of the scapular region; gill-mem- 

 branes five from 1 he- isthmus; gills J, a slit behind the fourth. JVeu- 

 dobranchia- small or obsolete. Tail isoceival. Dorsal iin very long, 

 the anterior part composed of low, free spines, the posterior of soft 

 rays; anal tin with or without spines; caudal fin separate or not. 

 Ventral fins wanting; pectorals small. Air-bladder present. Bran- 

 chiostegals C; pyloric COMM L! (in M<tN/<i<Ti>tl>r!iif<). Fishes of the fresh 

 waters of the Hast Indies, (lenera L'; species about 14. ~\Ye follow 

 Dr. Bean in attaching provisionally to this family ;i singular fish from 



