788 Bulletin 4^, Utttted States National Museum. 



This group comprises Acanthoptcri, with the ventral fins abdominal, 

 each of I spine and 5 rays, and the pelvic bones not attached to the 

 shoulder girdle; the spinous armature of the fins is less developed, 

 the scales are cycloid, and the opercles unarmed. The suborder marks a 

 transition from soft-rayed to spiny-rayed fishes, its nearest associates 

 among the latter being, perhaps, tlie Scombroid forms. The families here 

 defined are closely related, but whether other families, as ()phioceplmlid(v, 

 Ammodi/tida', etc., should be included, is not certain. From fishes of the 

 general character of Percesocea, the Hcmibraiicliii and Lopliobraiicliu seem 

 to be descended, and the Sijnentoijnathl are closely allied. The group is 

 composed chiefly of shore fishes and fresh-water fishes, mostly of small 

 size but some of them large aud voracious. (Ftrca, Perch; Esox, Pike.) 

 a. Lateral line wanting; teeth small or wanting; gill rakers long and slender. 



b. Species carnivorous, the body aud head elongate; vertebnu more than 35; dorsal spines 



slender, flexible, 3 to 8 in number; stomach not gizzard like. Atherinid.*;, cvi. 



bb. Species feeding on mud aud vegetation; the head short and broad; vertebra; about 24; 



stomach gizzard-like, with long intestines. Mugilid.i;, cvii. 



aa. Lateral line present; teeth very strong, unequal; gill rakers obsolete; head long and 



pointed; vertebrse about 24. Sphyb.'enid.e, cvm. 



Family CVI. ATHERINID^. 



(The Silversides.) 



Body rather elongate, somewhat compressed, covered with scales of 

 moderate or small size, which are usually, but not always, cycloid. No 

 lateral line ; some scales often with rudimentary mucous tubes. Cleft 

 of the mouth moderate. Teeth small, on jaws and sometimes on vomer 

 and palatines, rarely wanting. Premaxillaries protractile or not. Oper- 

 cular bones without spines or serrature. Gill openings wide, the gill 

 membranes not connected, free from the isthmus ; gills 4, a slit behind 

 the fourth. Pseudobranchiae present ; gill rakers usually long and slen- 

 der. Branchiostegals 5 or 6. Dorsal fins 2, well sei^arated, the first of 3 

 to 8 slender flexible sjiines, the second of soft rays ; anal with a weak 

 spine, similar to the soft dorsal, but usually larger ; ventral fins small, 

 abdominal, not far back, of 1 small spine and 5 soft rays; pectorals 

 moderate, inserted high. Air bladder present. No pyloric cceca. A-^erte- 

 brse numerous, usually about 23 -f- 23 = 46; third and fourth superior 

 pharyngeals coossified, with teeth. Carnivorous fishes, mostly of small 

 size, living in great schools near the shore in temperate and tropical 

 seas; a few species in fresh water; all the species have a silvery band 

 along the side ; this is sometimes underlaid by black pigment. Genera 

 about 15; species 60. All of them which are large enough are highly 

 valued as food, hence the common name of "fishes of the king," Pesca- 

 dos del Rey, or Pesce Re, or Peixe Rey. {Jfherinid(r, Giinther, Cat., iii, 

 391-409, 1861.) 



a Premaxillaries freely protractile, the skin not continuous with that of the forehead. 



b. Premaxillary narrow posteriorly, its edge nearly straight. Body little compressed, the 

 belly rounded; pectorals sliort; scales cycloid; vomer with teeth; first dorsal with 

 6 to 9 spines, inserted in front of the rather short anal; mouth short. 



Atiieuina, 352. 



