1880 Bulletin 4.7, United States National Museum. 



can not readily be thrown into subordinate groups. Almost every species 

 has an individuality of its own, and among the marine forms it is necessary 

 to recognize almost as many genera as species. It is impossible to throw 

 these small genera together into large groups. Of the American forms, 

 probably Jordania is nearest the primitive scaly stock, from which such 

 forms as Zaniolepis and Oxylebius are also descended. Remitripterus and 

 Nautichthys seem to be the most specialized genera. Fresh- water degener- 

 ation is exemplified in Coitus and Uranidea-j deep-water degeneration in 

 Zesticelus and Cottunculus, and the degradation associated with sluggish 

 habits in Ascelichthys, Psychrolutes, and Gilbertina. ( Triylidce, group Cot- 

 Una, part; group ScorfXBnina, part, Giinther, Cat., n.) 



I. Spinous dorsal evident, not concealed in the flesh nor indistinguishable from soft part ; 

 head with spines or tubercles (except in rare cases), its bones not all hidden in 

 lax skin. 



a. Ventral fins well developed. 

 6. Pectoral fins separate, not coalescent below. 



c. Ventral rays I, 5 ; vomer and palatines with teeth ; gill membranes broadly united, 

 free from the isthmus. 



JORDANIINJE : 



d. Body more or less scaly above, or with rough plates or prickles. 



e. Dorsal fin very long, of 17 spines; anal long; no slit behind last gill arch; 



back with rough scales ; sides with oblique serrated folds ; ventral fins 



well behind pectorals. JORDANIA, 703. 



ee. Dorsal fin moderate, of 12 or 13 spines; anal long; body very slender; 



sides of back with rough plates. 

 /. Last gill arch with no slit behind it ; chin with 2 barbels. 



PARICELINUS, 704. 

 ff. Last gill arch with a slit behind it ; chin without barbels. 



ALCIDEA, 705. 

 SCORP^ENICHTHYIN^E : 



dd. Body covered with smooth skin ; a slit behind last gill ; dorsal rays 11 ; body 

 rather robust. SCORP^NICHTHYS, 706. 



cc. Ventral rays not I, 5; usually I, 3, sometimes I, 2, or I, 4. 

 g. Spinous dorsal shorter than soft part, of less than 13 spines. 

 HEMILEPIDOTINJE : 



h. Body definitely more or less scaly above, the scales sometimes arranged in 

 bands, or sometimes modified as bony plates, these,usually placed along 

 lateral line or at base of dorsal (skin naked in Artediellu*) . 

 i. Last gill arch without slit behind it; gill membranes united, free from the 



isthmus. 

 j. Vomer and palatines with teeth. 



k. Preopercular spine with 1 to 5 enlarged hooks or antler-like processes 



above, besides the 2 on its bifid or emarginate tip. 

 L Back above lateral line evenly scaly ; spinous dorsal emarginate. 



CHITONOTUS, 707. 

 II. Back above lateral line with a series of enlarged plates or scales, 



the space above and below this naked. 

 m. Lateral line armed with a series of bony plates ; preopercular-like 



processes usually numerous. 



n. Dorsal fin with 1 or more of the anterior spines elevated and 

 filamentous ; scattered plates behind axil. 



TARANDICHTHYS, 708. 

 nn. Dorsal tin without filamentous spines ; no plates behind axil. 



ICELINUS, 709. 



