2740 Bulletin 4.7, United States National Museum. 



rows on each side of the dorsal; upon the disk they are placed above the 

 principal bones of the skeleton, most abundant upon its cranial portion ; 

 a single row of stout spines, usually 3-pointed, on the outer margin of 

 disk, a particularly large one at each outer angle ; body entirely smooth 

 below; snout very short, obtuse; bridge over the rostral cavity covered 

 in front with a 3-pointed spine, having on each side a simple spine ; short, 

 stout, simple spines upon each supraorbital margin, the front of which is 

 immediately above and behind the cavity containing the nostrils ; vertex 

 with several similar spines ; many spines closely placed upon the humeral 

 area ; numerous short tentacles upon margin of disk and on sides of trunk ; 

 supraoral cavity elliptical, small (horizontal diameter f- diameter of orbit), 

 containing a well-developed, club-shaped, very perceptible tentacle ; width 

 of opening of anterior nostril, which is in a short tube, \ that of posterior 

 nostril, which is not tubular; width of mouth much less than distance 

 between pupils and equaling diameter of orbit. Diameter of orbit 8 times 

 in distance from snout to base of caudal, 6 times in distance from snout to 

 origin of soft dorsal, 6 times in distance to origin of anal, 3 times in dis- 

 tance to base of ventrals, and 6 times in distance to angle between pec- 

 torals and trunk, 4f times in distance from snout to gill opening, 6 in 

 greatest width of disk, and nearly 2 in that of trunk ; width of interorbital 

 area f diameter of orbit. First dorsal ray longest, equal to diameter of 

 orbit; anal fin inserted under third ray of dorsal, with 4 rays, the third 

 or longest very slightly longer than the longest dorsal ray; ventral fins 

 inserted nearly under the middle of the disk, with 1 rudimentary and 5 

 dorsal rays, increasing in length posteriorly, the last and longest con- 

 tained 5 times in total length ; distances between origins of ventrals 6 in 

 total length; pectorals with peduncles entirely included in common mem- 

 brane, with blades far back, horizontal, lying close to trunk, composed of 

 16 rays, the middle or longest 3f in total length; caudal fin rounded, com- 

 posed of 9 rays, the external rays, 1 above and 2 below, simple, the others 

 bifid ; length of middle ray equal to that of trunk (measured from junction 

 of pectorals to base of caudal rays) and slightly exceeding the longest 

 pectoral ray. Length of intestine contained If times in total length. 

 Color, body covered above with reticulations of brown, the general hue 

 varying from light yellowish gray to grayish brown, the markings being 

 darker upon darker specimens ; pectoral and caudal fins with about 3 dark 

 bars; the terminal bars in young very black; body beneath milky white 

 (Goode & Bean.) West Indies, Gulf of Mexico, and Gulf Stream, in water 

 of moderate depth; taken by the Blake and the Albatross at numerous 

 stations in depths ranging from 10 to 95 fathoms. "As in Halieutcea, 

 Dibranchus, and allies, a rostral tentacle is present in this genus. Among 

 specimens belonging to the Museum of Comparative Zoology there is evi- 

 dence of the existence of a couple of distinct forms in the West Indian 

 waters. The true H. aculeatus is much the lighter in the ground colors 

 and has brownish reticulations across the back, 2 or 3 narrowish trans- 

 verse*bands of the same color across the pectorals, and 2 or 3 similar bands 

 appear on the caudal, the posterior being darkest. The margins of the 

 fins are light in color. The rostrum is acute ; it ends in a spine which 



