518 BULLETIN" 100, UNITED STATES NATIONAL MUSEUM. 



increase at the end of the low anterior arch in the lateral line. The 

 scales are armed very strongly by a sharply 3-angled spine, which 

 is about two-thirds as high as the width of the scale ; this spine from 

 its widened base is directed upward and backward at an angle of 

 about 65°, extending to a point directly above the hind margin of 

 the scale; this main spine is preceded by one to three smaller im- 

 bricate spinules ; a single spinule is sometimes present above or below 

 the median keel. In C. parallelus of comparable size there are three 

 to five parallel rows of several spinules, which increase in strength 

 along the median keel much less abruptly posteriorly. The scales 

 on the infraorbital ridge before middle of eye are in a single series 

 and bear two or three spinous keels like the main one on the scales 

 of the body; behind middle of orbit the scales of the infraorbital 

 ridge are armed by a single, very strong, broad keel, the main spine 

 of which is about one-third as high as the diameter of the pupil ; the 

 ridge ends in a single, hard, strong scale, pointed posteriorly, and 

 bearing a heavy, retrorse spine, which is preceded by a few small 

 spinules; this spine extends backward to within its own length of 

 the preopercular margin. The 12 scales on the median rostral ridge 

 bear about three series of spinules, except the last one, which has only 

 the strong median keel, composed of three spinules. The remaining 

 scales of the head bear but a single keel, like that on the body scales; 

 the spines on the ridges are greatly strengthened and enlarged ; the 

 height of the tip of the spines from the base of the occipital ridge 

 is about half the diameter of the pupil, being twice as great as in 

 C. parallelus. The four series of scales between the occipital ridges 

 converge backward to the middle of a naked area lying before the two 

 strong occipital scutes, which lie side by side, and represent the single 

 weaker median scute of O. parallelus. The series of scales midway 

 between the occipital and postorbital ridges is little enlarged ; about 

 three scales, larger than those surrounding them, extend backward 

 from the orbital rim to the preopercular ridge (a similar series occurs 

 in C. parallelus). The under surface of the head is completely 

 covered by deciduous prickle-like scales. 



The second dorsal spine is weak and smooth. The length of the 

 first dorsal base is contained 1.2 times in the interdorsal space, 2.4 

 times in the postorbital length of the head. The first ray of the 

 second dorsal fin is shorter than the pupil. The rays of the pec- 

 toral fin are slender and weak; the filamentous outer ventral ray 

 extends to the origin of the anal fin, and is equal in length to the 

 postorbital region of the head ; the other ventral rays are weak and 

 short, not nearly reaching to the anus. 



Color pale brownish in alcohol, black over the coelom; pale 

 greenish on head, becoming blackish on the opercles, about the 



