Jordan and Evermann. — Fishes of North America. 99 



a. PremaxiUarifS ami inaxillaiieH present, united liy suture aud imiiiovubly 



couni'cted to tlio craiiiuin ; otherwise as in AiimUn. Cauknciikli, P. 



ill. Preninxillaiy atropliicd or lost; inaxillaries lateral, more or less couflu- 



eiit with the palatiues; shoulder girdle nut attached to the skull. 



Al'ODES, Q. 

 h\i. (Jill airhes 5 or (i pairs; the jiosterior not modified into pharyngeals, and all of 

 them, as well as the shoulder girdle, disconnected I'roni the cranium; no 

 pahitopterygoid arch; no opercular elements. Lvomkui, 1!. 



</(/. iJody not truly eel-shaped; the vertebra; usually iu moderate or ratherlarge num- 

 ber (14 to 150); ventral fins usually present; gill openings typically ample; 

 jiremaxillary always present, aud maxillary usually so; shoulder girdle near the 

 cranium, usually but not always attached to it. 

 J. Hypercoracoid and hypocoracoid coalesced in a single lamellar imperforate 

 plate; scapular arch formed of proscapula and posttemporal, the latter 

 impinging on supraoccipital only; dorsal fin with many spines. 



Heteromi, V. 



jj. Hypercoracoid and hypocoracoid imperfectly difTereutiated, represented by a 



cartilaginous strip or plate, not perforate, aud without separate actinosts; 



ventrals abdominal; no fiu spines. Xenomi, W. 



jjj. Hypercoracoid and hypocoracoid well developed, not coalescent. 



A-. luterclavicles present; air bladder without duct; ventrals abdominal or sub- 

 abdominal, if jiresent; no niesocoracoid. 

 /. Gills pectinate; gill openings large; dorsal and ventral usually with 

 spines. Hemibrancuti, Z. 



U. Gills tufted; gill openings very small; opercle a simple plate; skin 

 with bony plates. Lopuouranchii, AA. 



hk. Interclavicles wanting, so far as known. 



»i. Preopercle entirely detached from the suspensoriiun, rudimentary and 

 attached only to lower jaw, its normal position taken by the sub- 

 opercle; no spines; no mesocoracoid. Lvopomi, U. 



mm. Preopercle normally connected. 



li. Mesocoracoid well developed; fins without spines; air bladder with 

 a persistent duct; pectoral fins inserted low; ventrals abdominal. 



ISOSPONDVLI, S. 



nil. Mesocoracoid always wanting. 



o. Ventral fins abdominal, without spines; no true spines in dor- 

 sal or anal fins, 

 p. Air bladder with a persistent duct; lower pharyngeals 

 separate. 

 I/. Shoulder girdle not connected with the skull iu the 

 usual way, the post-temporal barely touching the 

 cranium. (Mostly deep-sea fishes, with weak 

 skeletons.) I.niomi, T. 



y</. Shoulder girdle connected with the skull by a bifid 

 post-temporal. (Mostly fresh-water fishes, the 

 skeleton wellossified.) IIai'Lomi, X. 



IHK Air bladder without duct in adult; lower pharyngeals 

 fully united. Syne.ntognatiii, Y. 



00. Ventral fins usually anterior in position ; spines usually 

 present in the fins; pectoral fins not on the plane of the 

 abdomen ; parietal bones usually separated by the 

 supraoccipital. (Spiny-rayed fishes chiefly.) 



r. Pectoral fins not pediculate, the gill openings in 



front of them. AcAMHOPTEni, BB. 



rr. Pectoral fins pediculate, the basal bones reduced 



in number and elongate ; gills iu the axil of 



the pectorals. Pedici'Lati, CC. 



