968 Bulletin 47, United States National Museum. 



very blunt, rounded in profile. Mouth small, the maxillary not reaching 

 orbit. Caudal peduncle very short; anterior rays of dorsal and anal 

 little elevated. Lateral line high, a series of conspicuous pores above it 

 near the base of dorsal. Pectorals much longer than broad. Gill rakers 

 rather long, f diameter of eye. Bluish above, silvery below. Length 10 

 inches. Maine to Florida ; very abundant northward ; rare, and found in 

 deep water south of Cape Hatteras; an excellent pan-fish of fine flavor, 

 though less highly valued than its California congener, which it closely 

 resembles, (rpefc, three ; uKav6a, spine.) 

 Stromateus triacanflws, PECK, Mem. Amer. Ac., n, part 2, 48, pi. 2, fig. 2, 1800; Piscataqua 



River, New Hampshire; JORDAN, & GILBERT, Synopsis, 451, 1883; FORDICE, I. c., 313, 



1884. 

 Stromateus cryptoxis, MITCHILL, Trans. Lit. & Philos. Soc. N. Y., I, 1814, 365, plato 1, fig. 2, New 



York Bay; CUVIER & VALENCIENNES, Hist. Nat. Toiss., ix, 408, 1833. 



Rhombiis triacanthus, DE KAY, N. Y. Fauna: Fishes, 137, plate 26, 1842. 



Family CXXXVI. ICOSTEID^E. 



(THE RAG FISHES.) 



Body oblong, compressed, naked, prickly, or covered with small 

 cycloid scales. Head moderate, not externally bony, the opercles 

 unarmed. Mouth moderate, terminal ; premaxillary not protractile ; max- 

 illary moderate, without supplemental bone. Teeth small, in single series ; 

 vomer and palatines without teeth; no teeth in the throat or on thephar- 

 yngeals (in Icosteus or Acrotus). No barbels. Lower pharyngeals separate. 

 Branchiostegals 6. Gill openings wide, the membranes free from the 

 isthmus; gills 4, a slit behind the fourth; gill rakers slender. Pseudo- 

 branchise large. Pyloric cojca few. Air bladder present. Lateral line 

 present. Dorsal fin very long, continuous, without distinct spines ; anal 

 long, without spines ; caudal fin con vex, its peduncle slender ; ventral fins 

 thoracic, separate, but very close together, I, 4, or I, 5, wanting in one 

 genus; pectorals rounded, fleshy at base ; vent normal, without papilla. 

 Skeleton very soft and cartilaginous. Vertebrae in large number. This 

 group, as at present constituted, is composed of 4 quite diverse genera, 

 inhabiting the deeper waters of the Atlantic and Pacific. Dr. Gill unites 

 Icosteidce, with the Stromateidce. The reason of this association is not 

 evident, as the peculiar throat dentition seen hi the Stromateidce does not 

 occur in Icosteus or Acrotns. The Icosteidce show affinities with Centrolo- 

 phus, but apparently their recognition as a distinct family is justified. 



SCHEDOPHILIN^E: 



a. Body covered with small, cycloid scales; no prickles; ventrals I, 5; caudal rounded or sub- 

 truncate. 



b. Body elongate, not compressed at bases of vertical fins. ICICHTHYS, 442. 

 bb. Body ovoid, strongly compressed, especially at bases of vertical fins. 



SCHEDOPHILUS, 443. 



aa. Body scaleless ; ventral fins, if present, with the number of rays less than I, 5. 

 ICOSTEIN.ZE: 



c. Ventral fins present; caudal rounded. 



d. Ventral rays I, 4; fin rays and lateral line rough with spinules; dorsal very long, of 

 50 to 60 rays. ICOSTEUS, 444. 



