SCIADONUS. alfa 
preopercle are shorter, the uppermost being the longest of the three and the 
lowest the least developed. The angle at the end of each lower jaw is a 
spinelike prominence. Nape high, arched; a slight concavity on the crown. 
Snout massive, broad, more than twice as long as the eye, surmounted by a 
pair of sharp horizontally extended spines, Plate F, fig. 3a. Eye lateral, 
small, less than half as long as the snout, less than one seventh as long as 
the head, nearly one third as wide as the interorbital space. Mouth wide ; 
the cleft slightly rising forwards; maxillary nearly half as long as the head, 
reaching a considerable distance farther back than the orbit; lower jaws 
shorter, included. Teeth small, not very close together, in villiform bands 
on jaws, vomer, and palatines. Nostrils lateral. Bones of the skull soft, 
with large mucous cavities. Gill openings wide; membranes not united, 
free from the isthmus. Gill rakers short, slender; lamelle very short. No 
pseudobranchiz. Origin of the dorsal above the bases of the pectorals, pre- 
ceded in the specimen described by a couple of rudimentary spines. Anal 
origin below the eleventh or twelfth ray of the dorsal. A space at the cau- 
dal separating it from dorsal and anal was probably traversed by membranes 
uniting it with these fins. Ventral bases below the eye, fins each with two 
slender filamentary rays, the longer of which reaches quite to the vent. 
Vent below the middle of the pectoral fin. Existence of scales a matter of 
some doubt. Lateral line not apparent. 
Top of the head to below the eye whitish; mouth, chin and body* 
chamber black; from the origins of dorsal and anal backward cloudy 
brownish. 
The shape in this species is similar to that of A. armatus, the differences 
appear in the branchiostegal rays, the ventrals, the scales and the lateral 
line. 
Total length hardly more than three inches. 
Station. Latitude. Longitude. Depth. Temperature. Bottom. 
3381 4° 56’ N. 80° 52’ 30” W. 1772 fathoms 35.8° F. Gn. M. 
ScCIADONUS gen. n. 
Compressed and elongate in form; head massive, snout blunt. No eyes. 
Gill membranes free from the isthmus. Gill lamellze very short. Branchi- 
ostegal rays seven. Vertical fins united at their bases. Pectorals pedicel- 
late, narrow, long. Ventrals filamentary, small, of a single ray, close 
together, below the humeral symphysis. No cephalic spines. Opercles 
