980 Bulletin ^7, United States National Museum. 



pharyugeal inotlerately enlarged, elongate, not articulated to the cra- 

 nium, the fourth typically present; gills 4, a slit behind the fourth; gill 

 membranes free from the isthmus, and usually not connected with each 

 other ; pseudobrauchia; typically well developed. Brauchiostegals few, 

 usually 6 or 7. No bony stay connecting the suborbital chain to the pre- 

 opercle. Opercular bones all well developed, normal in position; the 

 preopercle typically serrate. No cranial spines. Dorsal lin variously 

 developed, but always with some spines in front, these typically stiff and 

 pungent ; anal fin typically short, usually with 3 spines, sometimes with 

 a larger number, sometimes with none; caudal fin various, usually lunate; 

 pectoral fins well developed, inserted high; ventral fins always present, 

 thoracic, separate, almost always with 1 spine and 5 rays. Air bladder 

 usually present, without air duct in the adult; simple and generally adher- 

 ent to the walls of the abdomen. Stomach ccecal, with pyloric append- 

 ages, the intestines short in most species, long in the herbivorous forms. 

 Vertebral column well developed, none of the vertebrae especially mod- 

 ified, the number 10 -|- 14, except in certain extra-tropical and fresh-water 

 forms, which retain the primitive higher numbers. Shoulder girdle 

 normally developed, the post-temporal bifurcate, attached to the skull, 

 but not coosified with it; none of the epipleural bones attached to the 

 center of the vertebra^ ; coracoids normal, the hypercoracoid always 

 with a median foramen, the basal bones of the pectoral (actinosts or 

 pterygials) normally developed, 3 or 4 in number, hourglass-shaped, 

 longer than broad ; premaxillary forming the border of the mouth, 

 usually protractile ; bones of the mandible distinct. Species very 

 numerous, found in all seas except those of the Arctic regions. Many 

 species inhabit fresh waters, especially in North America and Europe. 

 These fresh-water forms are apparently nearer the primitive stock than 

 the marine species are. The Elat^fsODiida', Centrarchldcv, and Fercidw are 

 the most primitive, and apparently form, with the Percopsulw and Aplire- 

 doderida', an almost continuous series. This series we are compelled to 

 break in a linear arrangement for the purpose of bringing in other series 

 of transitional forms, which culminate in the Berycoids and the Scombroids. 



a. Maxillary not sheathed by the preorbital, or only partially covered by the edge of the latter; 

 ventral with its accessory scale very small or wanting; pectoral without accessory scale; 

 sheath at base of spinous dorsal little developed; vomer usually with teeth; opercle 

 usually ending in a spine. 

 b. Precaudal* vertebra; with transverse processes from the third or fourth to the last; 

 ribs all but the last 1 to.4, sessile, insirtod on the centra behind the transverse pro- 

 cesses; anal spines 3 or more. 

 c. Pseudobranchiw rudimentary, covered by tlie skin. 



d. Lateral line wholly wanting; dorsal spines 4 or 5; vertebrw about 10-t-14 = 24. 



ELASS0MID.T:, CXL. 



dd. Lateral line more or less developed; dorsal spines 6 to 15; vertebra' 29 to 33. 



CENTRABCHIDiE, CXLI. 



cc. Pseudobranchia; large; dorsal spines about 10; vertebra? 10 -|- 15 = 25. 



KUHLIln.'E, OXLII. 



hb. Precaudal anteriorly without transverse processes; all or most of the ribs inserted on 

 the transverse processes when these are developed. 



* These characters are taken from Boulenger, Cat., i, p. 2. 



