MONOMiTOPus TOR^^:s. 157 



rudimentary. Gills four, a slit behind the fourth, lamellae very short. Gill 

 membranes not united, free from the isthmus. Eye lateral. Snout short, 

 blunt. Opercular and preopercular spines present. Pyloric caeca short, 

 comparatively few. Ventrals near the humeral symphyses, 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- 

 branchia?, and may belong to one of the two subgenera typi.^ed by the 

 species described below and figured on Plate XL., Ilonomitopus torvus and 

 Moiiomeropus mcdlspinosus. 



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 ; Lh ca. 190; 

 Itr. ca. 5-5. 



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. Pseudobranchias 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. Ansil 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 



