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U. S. P. K. K. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



and so closely approximated that the interocular space consists of a mere bony ridge ; they are 

 situated on the left side, and their horizontal diameter is contained four times in the length of 

 the side of the head, somewhat less than once in advance of the anterior rim of the orbit. 



The origin of the dorsal fin takes place near the nostril, on the right side of the anterior rim 

 of the upper orbit ; its rays are gradually increasing in height to near the posterior third of the 

 extent of that fin, to diminish again rather rapidly backwards. It terminates near the base of 

 the caudal without being contiguous to it. The anal commences on a line situated posteriorly 

 to the base of the pectorals, and terminates almost evenly with the dorsal ; its middle rays 

 being somewhat deeper than those of the latter fin are high. The caudal fin, which enters 

 about six times in the total length, is sub-lanceolate or convex upon its posterior margin. The 

 right pectoral fin is smaller than the left, which is but moderate sized, and rather more 

 tapering. The ventral fins are small also, though proportionally broad at their base or 

 insertion, which is partly opposite the base of the pectorals and partly anterior On the 

 accompanying figure they are represented too much forwards. There are six branchiostegals 

 on the left side and five only on the right ; the branchial aperture being continuous under the 

 throat. 



Br. VI ; V ; D 82 ; A T2 ; C 1, 1, T, 6, 1, 1 ; V 6 ; P 1, 10. 



The only rays that are bificated or dichotomised may be observed in the caudal and left 

 pectoral. The scales are of moderate size, longer than deep, sub-elliptical, and finely 

 pectinated upon their posterior margin ; their anterior section exhibiting radiating grooves. 

 They cover the opercular apparatus and cheeks, extending likewise to some of the fins. The 

 lateral line takes nearly a straight course from the suprascapular region to the base of the 

 caudal, it being but slightly raised anteriorly. The ground color is of a soiled yellow ; the 

 scales being margined and the fins speckled with blackish. 



Reference to the figures. Plate XLb, fig. 1, represents the left side of Psetticlitliys sordidus, 

 size of life. Fig. 2 the right side of the same. Figs. 3 and 4 are scales of the lateral line 

 from either side ; the other scales were not preserved on ths specimen. 



Specimens from Presidio exhibit upon their body and fins irregular small black spots, in 

 addition to the color elsewhere alluded to. 



List of specimens. 



