NEW COTTID FISHES BOLIN 27 



NoviRicuzENius,! new subgenus 



Genotype. — Ricuzenius nuditliorax. 



Mandibular branch of lateral line system composed of moderately 

 large, simple pores. A well-developed slit behind the last gill arch. 

 Sides of head below midline of orbit, naked; scales on ventral por- 

 tion of body much reduced in size and number. 



RICUZENIUS NUDITH0RAX,= new species 



Figure 5 



Description. — Depth of body, measured from origin of first dorsal 

 to pelvic base, 4.8 in standard length, 1.6 in head; width at dorsal 

 end of pectoral base 2.0 in head. Dorsal body contour forming a 

 very gentle sigmoid curve, the ventral contour a very gentle convex 

 curve, from the deepest point to the caudal peduncle, the least depth 

 of which is 1.6 in orbit. 



Head 3.0 in standard length; snout 1.1 in orbit, forming an angle 

 of about 67° with chin, of about 148° with frontoparietal region. 

 Lower jaw slightly shorter than upper, barely included. Eye rather 

 small, diameter of orbit 3.3 in head. Interorbital space flat, its 

 width about 4.0 in orbit, 1.5 in posterior width of maxillary. Top 

 of head flat, without any well-defined frontoparietal ridges. Nasal 

 spines slender, sharp, equal to about 0.6 interorbital space. Pores of 

 head moderate in size; a series bordering suborbitals both dorsally 

 and ventrally. 



Origin of first dorsal very slightly in advance of upper end of 

 gill opening; base of fin 1.7 in head; fin of 10 spines; the first two 

 with approximate bases, very slightly shorter than third spine, which 

 is longest, being 2.2 in head. Second dorsal contiguous to first dorsal ; 

 base of fin 2.6 in standard length; fin of 21 rays; first ray 2.0 in 

 fifth ray, which is longest, being 1.9 in head. Origin of anal about 

 under second dorsal ray, its posterior end under second ray from 

 end of second dorsal; base of fin 2.9 in standard length; fin of 

 19 rays; tenth to sixteenth rays subequal and longest, being 2.6 in 

 head. Pectoral base 3.2 in head; fin of 16 rays; longest ray 1.1 in 

 head, extending to level of seventh anal ray. Base of pelvics behind 

 lower end of pectoral base at a distance equal to about 0.4 pupil; 

 length of fin 2.3 in head; fin extending about 0.6 distance to anal 

 origin. Caudal truncate; with 9 split rays; its length 1.5 in head. 

 Anus in advance of anal origin at a distance equal to about 0.5 

 orbit; located just anterior to the base of a short, bluntly conical, 

 genital papilla, which is about equal in length to nasal spines. 



' FVom noiius, npw 4- Ricuzp.nius. 



' From ntidus, naked + thorax, breast. 



