272 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



a. Compressed tubercles or pointed spines over eye and at oeci]int; no tilaments 

 behind eye. 



}>. Anal rays 12; second preopercular spine moderate .polyacanthocephalus, 21. 



bb. Anal rays, 14; second preopercular spine very short, not one-fourth length of 

 upper; anal fin usually plain; head very long and flat; body with round, rough 



plates above ' jaol-, 22. 



bbb. Anal rays, 13; second preopercular spine long, one-third or more length of 

 upper; anal fin with 4 black crossbands; spines and ridges on top of head high 



and sharp; top of head sparsely covered with warts edomius, 23. 



aaa. No spines or tubercles over eye or occiput; a pair of postorbital filaments; pre- 

 opercular spines 3. 

 c. Ridges on head high and continuous; interorbital space and top of head deeply 



concave; lower parts wnth small white spots nivosus, 24. 



cc. Ridges on head scarcely developed; interorbital space shallowly concave; top of 

 head evenly rounded from side to side; chin and throat with black and w^hite 

 markings .ranmw.s, 25. 



21. MYOXOCEPHALUS POLYACANTHOCEPHALUS (Pallas). 



Coitus polyacanthocephalus Pallas, Zoogr. Rosso- Asiat. , III, 1811, p. 133; 



Aleutian Islands; no definite locality. — GtJNTHER, Cat.. II, p. 166. — Jordan 



and Gilbert, Synopsis, 1883, p. 704. 

 Myoxucephalus polyacanthocepJtalus Jordan and Gilbert, U. S. Fur Seal Comin., 



Ill, p. 463, pi. lxiii; Unalaska, Robben I., St. Paul, Unga, etc. — Jordan 



and Evermann, Fish. N. and iSI. Amer.. II, p. 1976. 



Fig. 17. — Myo.xocephah s polyacanthocephalus. 



Head 2i in length; depth 4i; D. IX or X-13 to 16; A. 11 to 13. 

 Body rather elongate. Head long and narrow, somewhat compressed, 

 concave between the or])its. the orbital rim ])eing elevated; lower jaw 

 included; nasal spines strong; a strong ridge above eye, with a blunt, 

 compressed spine behind it; behind this a small digitate cluster of 

 ridges ending in low spines; behind these an irregular, ])roken ridge 

 on each side of the vertex, extending to the occiput; outside of this 

 another ragged ridge; suborbital stay strong, striate; upper preoper- 

 cular spine very long, straight, simple, striate at base, longer than 

 eye; a similar but shoi'ter spine })elow it, not one-half as long, and the 

 usual downward-directed spine at lower edge of preopercle and sub- 

 opercle; opercular spine moderate. Skin of top of head thin, with 



