268 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



Head 4f to 4^ in length; depth 5 to 5f. Least depth of caudal peduncle 

 2| in length of head. Dorsal 44 or 45; anal 33; ventrals i, 5; pectorals 17. 

 Br. 6. Pyloric caeca large, 4 in number. 



The mouth is very oblique, larger than in R. hypoplecta, the maxillary 

 extending beyond the vertical from the middle of the orbit, contained 2f in 

 the length of the head. In the front of the premaxillaries, the teeth are in 

 a broad villiform band, with an outer series of moderate canines; laterally the 

 band diminishes rapidly in width, the outer series of reduced canines alone 

 reamining near angle of mouth. The mandibular band is wider than the 

 premaxillary band, but likewise tapers to a single series laterally. The 

 outer series is more or less enlarged, i or more larger canines sometimes pres- 

 ent at the middle of each side of the jaw. Very broad bands of minute 

 villiform teeth cover continuously the vomer and the adjacent portions of the 

 palatines, the two separated only by narrow oblique lines. The transverse 

 length of the vomerine patch slightly exceeds the length of the palatine 

 patches, the width of the patches but slightly less than their respective 

 lengths. Eye equal to length of snout, \ length of head, the snout a trifle 

 longer in the cotype. The interorbital width is narrow, \ or | the diameter 

 of the orbit. Gill membranes with 6 rays, broadly joined across the throat, 

 forming a free fold, the width of which equals the diameter of the eye. Gill 

 rakers short, almost tubercular, spinous, 13 in number. A short slit is 

 present behind the last gill arch, which bears a double set of filaments. 

 The pseudobranchiae are well developed, but form a small patch. Parallel 

 with the outer gill arch there is attached to the inner surface of the 

 cheeks, a wide membranous fold, the free edge of which is produced into a 

 series of short processes equaling in size the gill rakers of the outer arch, and 

 alternating with them. They thus form an interlocking mechanism between 

 the fold and the outer gill arch, and function in the same manner as the gill 

 rakers of succeeding arches. Pores are developed on the head as in related 

 species. The cheeks are covered with very fine scales, the rest of the head 

 naked. 



The posterior border of the orbit is midway between the tip of the snout 

 and the origin of the dorsal fin. The first 5 dorsal rays are unbranched, and 

 are distinctly articulated, with the possible exception of the first and second 

 rays. The first anal ray is concealed in the membrane, unbranched and 

 unarticulated; the succeeding anal rays are all branched and articulated. 

 The longest dorsal ray is half as long as the head. The caudal is 

 broadly rounded, a trifle shorter than the pectoral, f to f the length of the 

 head. The width of the pectoral base equals the length of the snout and 

 half the eye. The ventrals are inserted in advance of the pectorals; the 

 inner rays are the longest, and reach half way from the base of the fin to the 

 vent. 



The scales are small, evidently ctenoid, but minutely so. They are reduced 

 in size and appear cycloid on the breast and belly, and in advance of the 

 pectoral fin. There is a wide naked strip in front of the dorsal fin. The 

 lateral line runs high and parallel with the back, containing 83 pores, and 

 terminating at a distance from the base of the caudal equaling half the 

 length of the head. The lateral line consists of a series of vertically elongate 

 slits, which give the appearance of enlarged scales, but do not correspond 

 with the scales in any way. In Ronquilus jordani the same structure has 



