Jordan and Evermann. Fishes of North America. 1M) 



u. Premaxillaries and maxillaries present, united by suture aud immovably 

 connected to the cranium; otherwise aa in Ayodvs. CARENCHELI, P. 

 Hi. Pieiiwxillary atrophied or lost; maxillaries lateral, more or lea conflu- 

 ent with the palatines; shoulder girdle not attached to the skull. 



APODES, Q. 



hh. (Jill aivhes "> or (', pairs; the posterior not modified iuto pharyn^eals, and all of 

 them, as well as the shoulder girdle, disconnected from the cranium; no 

 palutopterygoid arch ; no opcrcular elements. LYOMKRI, R. 



gg. body not truly eel-shaped; the vertebrae usually in moderate or rather largo num- 

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

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

 cranium, usually but not always attached to it. 



j. Hypercoracoid aud hypocoracoid coalesced in a single lamellar imperforate 

 plate; scapular arch formed of proscapula ' and postteniporal, the latter 

 impinging on supraoccipital only; dorsal fin with many spines. 



HETEEOMI, V. 



jj. Hypercoracoid and hypocoracoid imperfectly differentiated, represented by a 

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

 ventral* abdominal; no fin spines. XENOMI, W. 



jj}. Hvporcoracoid and hypocoracoid well developed, not coalescent. 



k. Interclavicles present; air bladder without duct; ventrals abdominal or sub- 

 abdominal, if present; no mesocoracoid. 



I. Gills pectinate; gill openings large; dorsal aud ventral usually with 



spines. HEMIBRANCHII, Z. 



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



with bony plates. LOPHOBRANCHII, AA. 



kk. Interclavicles wanting, so far as known. 



TM. Preopercle entirely detached from the suspensorium, rudimentary and 

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

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



mm. Preoperclo normally connected. 



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

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



ISOSPONDYLI, S. 

 nn. 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. 



* q. Shoulder girdle not connected with the skull in the 



usual way, the post-temporal barely touching the 



cranium. (Mostly deep-sea fishes, with weak 



skeletons.) INIOBII, T. 



qq. Shoulder girdle connected with the skull by a bifid 



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



skeleton well ossified. ) HAPLOMI, X. 



pp. Air bladder without duct in adult; lower pharyngeals 



fully united. SYNENTOGNATIII, Y. 



oo. 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. ACANTHOPTEKJ, I5B. 



rr. Pectoral fins pediculate, the basal bones reduced 



in number and elongate; gills in the axil of 



the pectorals. PEDICULATI, CC. 



