2078 Bulletin 4.7, United States National Museum, 



upper rays longest, the lower becoming regularly shortened; bones of 

 head thin and yielding, the system of mucous canals very strongly 

 developed. Deep-sea Agonoids. (fiaQv$, deep; Agonus.} 



2422. BATHYAGONUS NIGRIPINMS,* Gilbert. 



B. 6; 1 D. 6 to 8; 2 D. 6 or? ; A. 7 to 9; P. 15 or 16; V. 3 (I, 2) ; C. 1-11-1 ; ver- 

 tebrae 11 + 34 = (45). Pyloric caeca 5 (1 individual). Body depressed 

 throughout, depth | of width, the latter 9f in body length; sharply octag- 

 onal, tail strongly depressed hexagonal, its lateral faces very narrow. 

 The ridges compressed ; the small sharp spines present on all the ridges 

 from head to caudal except 011 the median ventral series of peduncle and 

 the first few plates behind the pectoral in the imperfect lateral series. 

 One to 3 pairs of plates between last ray of second dorsal and first median 

 plate, and 1 or 2 pairs between last anal ray and first median plate ; 1 or 2 

 plates in front of and 4 or 5 small, sharply spinous plates on base of pec- 

 torals; about 22 plates, radially striate, elevated at the center, some of 

 the strongest minutely spinous, on breast in a median and 2 lateral rows 

 (the latter continuous with the ventrolateral series) and in the ridge-like 

 rows forming the edges of breast ; 110 plates medially on posterior part of 

 the branchiostegal membrane or laterally on the anterior part ; from 1 to 3 

 or 4 well-developed plates on front part of lower side of lower jaw; the 

 membranaceous interval behind vent, between the ventrolateral series, 

 occupied by about 5 to 9 plates, partly arranged in pairs; none between 

 ventrals and vent. Head 4| to 5 in body, much depressed, its greatest 

 depth | of its greatest width, the latter equaling width of body; snout 

 broad, flat, shovel-like, nearly equal to long diameter of orbit; orbit 

 oblong-oval, its vertical diameter of the longitudinal, the latter 3 or a 

 little less in head; interorbital space concave, about as in trlacanthiis, but 

 broader, with a pair of minor longitudinal ridges, about 9 in head, about 

 2 in vertical diameter of orbit; the moderate supraocular ridges ending 

 in a sharp spine, the scarcely developed occipital ridges with 2 pairs, of 

 which the anterior is low and blunt; the well -developed temporal ridge 

 with 2 or 3 small spines and terminating in a larger suprascapular spine; 

 bridge across cheek close under orbit with about 1 spine on preorbital, 3 

 on suborbital, and ending in 1 on preopercle; 1 of about the same size 

 below the last on preopercle. Cheek below ridge with 2 to 4 (usually 3) 

 spinous plates; nasal spines small, sharp, directed backward; movable 

 median rostral plate small, varying in size and shape (disappearing with 

 the prolongation of lower jaw), its lateral expansions usually free, as 

 spines; 3 small upright diverging spines (only 2 systematically placed in 

 1 specimen). Mouth oblique, lower jaw somewhat protruding, maxillary 

 scarcely reaching front of orbit. Teeth moderate, present on jaws, vomer, 

 and palatines. Two barbels, 1 large and the other small, at tip of inaxil- 



* Diagnosis: Body sle.nder, tapering uniformly, depressed throughout, its depth | of its 

 width at base of pectorals, the latter 9g in length; head 4 to 5 in length. Plates in the 

 dorsal series 43 or 44 ; between occiput and first dorsal 7 or 8 ; between dorsals 6, some- 

 times 7; between ventrals and anal 13 to 15 pairs. Lower jaw protruding; 2 barbels at 

 ip ot each maxillary ; median rostral plate present, with 3 small diverging spines; nasal 

 spines small separate; 1 pair supraocular and 2 pairs occipital spines. Gill membranes 

 joined to isthmus. Under side dusky, lighter above ; all the fins blue black. 



