156 DEEP SEA FISHES. 



body is compressed and slender; its greatest depth is about one tenth of 

 the total length ; the length of the body cavity is contained three and one 

 half times in the total. Head one seventh of the entire length; Avidth of 

 the parietal section equal to the rostrorbital length ; arched across the 

 crown and forehead, and flattened some above the orbits ; cephalic sjjines 

 short, opercular spine with a keel ; angles low. Snout broad, blunt, broadly 

 rounded in front, as seen from above, length equal to the width across the 

 eyes, or to one and one half times the length of the orbit. Mouth large, 

 cleft nearly half the length of the head ; maxillary extending one half the 

 orbital length backward of the orbit, greatest width three fourths of the 

 length of the oi'bit, upper, lower, and hinder margins concave. Teeth very 

 small, in villiform bands on jaws, jDalatines, and on the V-shaped end of the 

 vomer. Eye moderately large, two thirds of either rostral length or width 

 of interorbital space, less than one fiftli as long as the head. Bones of the 

 skull thin, mucous cavities greatly developed. The two series of preopercu- 

 lar spines are quite small and short ; tlie other spines of the head are lo- 

 cated as in P. longkcps, but are so small as to be found more readily by the 

 touch than by the sight. Dorsal origin but little backward of the axil of 

 the pectorals. Anal origin below the twenty-third ray of the dorsal fin. 

 Pectorals small, narrow, four sevenths as long as tlie head. Ventrals of 

 two filamentary vnys, separate nearly to their bases ; longest ray as long as 

 the pectoral fins. Caudal region slender, fin thread-like. Lateral lines 

 three, more distinct anteriorly, uppermost short. 



Sides of the head, from the nostrils, maxillary and operculum, and chin, 

 belly, and fins black; top of head to suborbital tract white ; muscular tracts 

 light reddish brown. There are indications of a red or purple cast over the 

 muscles and the bases of the fins in life. 



MONOMITOPUS. 



Monomitopiis Aloock, 1890, Ann. IMag. N. H., VT., 297. 



Body and head compressed, covered Avith scales. Head short and deep ; 

 skull with median keels. Lateral line near the dorsal fin, distinct anteriorly. 

 Mouth anterior, wide, oblique. Teeth small, numerous, in villiform bands 

 on jaws, vomer, and palatines. Eight branchiostegal rays. Pseudobranchioe 



