2562 Bulletin ^y, United States National Museum. 



form, in bands, on the jaws only ; tip of lower jaw with a barbel ; premaxil- 

 lary protractile. Dorsal tins 2, the first short and high, of stiff, spine-like 

 branched rays ; the second dorsal very long, usually of very low feeble 

 rays, continued to the end of the tail ; anal tiu similar to the second dorsal, 

 but usually much higher; no caudal fin; ventrals small, subjugular, each 

 of about 8 rays. Branchiostegals 6 or 7. I^ateral line present. Gills 3^ or 

 4, a slit behind the fourth. Gill rakers small; gill membranes free or nar- 

 rowly united to the isthmus, usually more or less connected; pseudo- 

 branchiie wanting or rudimentary; pyloric ca-ca numerous; air bladder 

 present. Genera 18; species about 50, chiefly of the northern seas, all in 

 deep water. They diftVr from the codfishes chiefly in the elongate and 

 degenerate condition of the posterior part of the body. Dr. Gill suc- 

 cinctly defines the group as "Gadoidea with nn elongated tail tapering 

 backward and destitute of a caudal fin, postpectoral anus, enlarged sub- 

 orbital bones, inferior mouth, subbrachial ventrals, a distinct anterior 

 dorsal, and a long second dorsal and anal converging on end of tail." We 

 here follow Goode & Bean in the general arrangement of the genera of 

 Macroin'ido'. Some of these can, however, be only provisionally adopted, 

 as the characters of tlentition, form of month, and character of the second 

 dorsal spine or ray, are subject to much intergradation. These characters 

 seem much more distinct on paper than they are in fact. Still, most of 

 the genera here adopted will ultimately prove valid. {Macruridce, 

 Gliuther, Cat., iv, 390-398, 18G2.) 

 a. First branchial arch free, without fold of niembrane across it ; mouth large; secoml 

 dorsal well developed, higher thau the anal. 

 BATHYGADINjE : 

 b. Gills 3-J ; snout short and blunt, the jaws even in front ; teeth in villiform bands, 

 sometimes obsolete ; bones of head soft and cavernous ; scales smooth ; first 

 dorsal low, its spine not produced. Bathyoadus, 995. 



TRACHYRINCHIN.E : 



66. Gills 4; snout rather long. 



0. Teeth in upper jaw in 2 series, the outer enlarged, those in lower jaw 

 in 1 series; mouth subterminal; barliel obsolete; nape without scale- 

 less fossae ; vomer with teeth ; bones of head soft and cavernous ; tail 

 very long, flagelliform ; anal flu with an elevated anterior lobe. 



Steindachneria, 996. 

 cc. Teeth in both jaws in villiform bands; barbel developed; mouth inferior; 

 a naked fossa on each side of nape ; a row of armed scales along base 

 of dors.il anteriorly ; opercle very small ; anal not elevated in front. 



Trachyrincus, 997. 



MACKOURIN^ : 



aa. Pirst branchial arch with a fold of membrane across its terminal portion; gills 4, a 

 sUt behind the fourth ; barbel well developed. 

 d. Teeth not .all in villiform bands, those of lower jaw in 1 series; mouth rather 

 large, with nmre or less of lateral cleft. 

 e. Upper jaw without villiform band behind the enlarged anterior teeth, the 

 inner teeth, if present chiefly uniserial, not in villiform bands. 

 /. Dorsal fins widely separated, the interspace greater than base of first. 

 g. ITirst dorsal with the spine not serrate, its insertion over pectoral 

 or nearly so; pectoral placed high, opposite upper angle of 

 gill clett: scales small, bristly; bones of head cavernous; 

 ventrals short and weak. Malacocephalus, 998. 



gg. First dorsal with its spine more or less strongly serrate; pectoral 

 inserted below upper angle of gill cleft. 



