DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 501 



Tentacle represeiitinj;- first dorsal liii retractile, with dilated trilobate tip. Soft dorsal 

 flu seven-rayed, inserted ijosterior to discal margin. 



Anal fin behind dorsal. Pectorals median, carpus narrow, slightly exserted, horizon- 

 tally placed. 



Ectoderm covered with numerous and strong stellular spines, above and below; the 

 spines being particularly strong and three-pointed at the margins of the disk. Tongue, air 

 bladder, and pyloric appendages wanting. 



DIBRANCHUS ATLANTICUS, Peters. (Figure 413.) 



Dihrancluis aUanlicus, Peters, Monatsberichte, Koniglich Preussisclien Akademio, Wissenschaften, Berlin, 

 1875 (76) 736), Coll. of H. M. S. GazelU, coast of W. Africa, lat. 10^ 12' 9" N; Ion. 17^ 25' 5" W; dei.tli, 

 360 fuis.); plato with 5 figs.— GOnther, Challenger Rep., xxii, 59.— Vaillant, Travailleur, 1888, 313. 



SalieitUea seuticosa, Goodk, Proceedings U. S. Nat. Mus., ill (sig. 29, Jan. 31, 1881), 67. (Coll. of U. S. F. 

 C, 1880, oft" Newport, R. I., depths 225 and 238 fius.),— Jordan and Gilbert, Bull, xvi, U. S. Nat. 

 Mus., 851. 



A species of Bib ranch ns with orbicular disk, nearly as wide as long; its length about 

 half that of the body ; its lateral outline prolonged on each side, and terminating in a strong 

 spine, armed at the tip with a group of irregularly arranged acicular spinelets. Body cov- 

 ered above with numerous stout, conical spines with stellular ba.ses. These are largest 

 upon the trunk, where they are approximately arranged in about four irregular longitudinal 

 rows upon each side of the dorsal fin. Closely set rows of these stout spines mark the outer 

 margin of the disk, and there is also a cluster of five to seven upon each carpal peduncle. 

 Outside of these marginal spines, upon each side, is an irregular marginal row of five de- 

 pressed, knife-like spines, each tipped with a crown of three acircular spinelets. On the 

 anterior margin of the disk the two rows coalesce to a greater or less extent and form a 

 bristling array of closely set .spines, some pointing dorsally, sonic laterally, some ventrally. 

 There are two kinds of spines upon the dorsal surface, in addition to the large ones already 

 described ; some large,somewhat remote from each other, conical, stellular ; others, muchmore 

 numerous and filling the interspaces, prickle-like, stellular. Belly armed with numerous 

 closely set spines of a similar kind. Snout somewhat projecting, armed with three many- 

 tipped spines. A spine-arnicd ridge in front of the eyes, over the top of the snout. In this 

 4 spines are conspicuous, one in front of each eye, and between these a larger pair, in front 

 of the, supraorbital ridges. From these last-mentioned spines extend spine-armed ridges 

 . ah)ng the upper margins of each orbit. Under the snout is a cavity (horizontal diameter 

 i that of orbit) containing a barbel, pedicelled, with thick, club-shaped, trilobate tip. On 

 each side of this cavity are the nasal openings, which are as in Ralieutichtliys. 

 < The width of the mouth is equal to the distance between the centers of the pupils of 

 the eyes. 



The diameter of the orbit is contained as follows in other dimensions of the body : In 

 total length, 9J; in distance from snout to dorsal, 6; same to anal, 7; the base of ventrals, 

 3; to angle between pectorals and trunk, 5i; to gill opening, 5; in greatest width of disk, 

 5i; of ti-unk, i. Width of interorbital ;irea in diameter of orbit, |. 



Dorsal flu with G or 7 rays, the longest (3d) IJ times diameter of orbit, and G times in 

 total length. Anal fin inserted entirely behind dorsal, with i rays, the longest (3d) about 

 as long as longest in dorsal fin. Ventral fliis inserted nearly under middle of disk, a little 

 nearer to vent than to mandibular symphysis, with one rudimentaryandflve well developed 

 rays, increasing in length i>osterioily, the last and longest Gi times in total. Distance 

 between ventral origins, 7.J in total length. 



Pectorals with peduncles slightly exserted, bases included in common membrane, com- 

 posed of 13 to 15 rays, the longest (3d or -Ith) -ij in total. 



Caudal flu rounded, consisting of 9 rays, all bifid or trifid except the two external 

 ones; length of middle ray, about half that of trunk and exceeding that of the pectoral, 

 being contained i!^ times in total length. 



