MONOMITOPUS TORVUS. 157 
rudimentary. Gills four, a slit behind the fourth, lamella very short. Gill 
membranes not united, free from the isthmus. Eye lateral. Snout short, 
blunt. Opercular and preopercular spines present. Pyloric ceca short, 
comparatively few. Ventrals near the humeral symphysis, close together, 
with a single ray. Pectorals small, simple. Vertical fins united and their 
bases invested by thick skin and scales. Species with a narial groove. 
The type specimen of Dicromita Agassizii G. B., has small pseudo- 
branchiz, and may belong to one of the two subgenera typified by the 
species described below and figured on Plate XL., Monomitopus toreus and 
Monomeropus malispinosus. 
Monomitopus torvus sp. n. 
Plate XL. fig. 1. 
Br. r.8; D. 107-111; A. 86 to 95; V.1; P. 32-33; C. 8; LI. ca. 190; 
ltr. ca. 55. 
Body and head compressed, tapering; depth four fifths of the length of 
the head. Head about one fifth of the total length, arched across the fore- 
head. Snout longer than the eye, little narrower forward, blunt, not swol- 
len but slightly prominent above the mouth. Eye moderately large, hardly 
one fifth of the length of the head, two thirds as wide as the interorbital 
space, four fifths as long as the snout. Mouth large, maxillary extending 
backward behind the orbit one third of the diameter of the latter. Teeth 
small, equal, on jaws, vomer and palatines, in villiform bands. Vomerine 
teeth in a V-shaped band, in which the apex is forward and swollen. Poste- 
rior nostril near the front of the eye; anterior near the end of the snout, 
with a slight groove to the lip. Gill apertures wide; membranes not 
united, free from the isthmus. Pseudobranchiew rudimentary. Gill rakers 
slender, two thirds as long as the eye, ca. 8 + 18. Opercular spine strong. 
Preopercular spines short, compressed, rather wide in the bases. Suborbital 
bones prominent, reaching down in a sharp edge over the maxillary. Basal 
portions of fins with thick skin and covered by scales. Dorsal origin above 
the axil of the pectoral. Anal origin below the twenty-second ray of the 
dorsal, twice the length of the head from the end of the snout. Caudal 
narrow, slender, about two fifths as long as the head, acute, united with dor- 
sal and anal near the base. Pectoral short, comparatively deep, half as long 
as the head. Ventrals very small, threadlike, as long as the pectorals, close 
