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U. S. p. R. R. EXP. AKD SURVEYS — ZOOLOGY — GENERAL REPORT 



List of specimens. 



2. AMBLODON SATURNUS, Grd. 



Spec. Char. — Profile of the head slightly depressed at the ocular region. Snout thick and rounded. Posterior extremity of 

 maxillary even witli a vertical line intersecting the pupil. Extremities of pectorals not extending as far as the tips of the 

 ventrals, which do not reach the vent. Caudal fin posteriorly rectilinear. Ground color of upper regions purplish brown ; of 

 the inferior regions, greyish or yellowish, each scale bearing a dark purplish spot upon its middle ; which spots are sometimes 

 confluent, so as to constitute narrow streaks, corresponding somewhat to the rows of scales. An opercular patch. An obso- 

 lete, liglil fascia may also be observed across the middle of the body. Fins rather dark. Belly and throat sometimes unicolor, 

 golden yellow. 



The general appearance of this species is proportionally shorter and deeper than either A. 

 grunniens or A. concinnus. According to all appearances, it is a species of rather small dimen- 

 sions. The specimens now hefore us are hut six inches in total length, the head constituting 

 the fourth of it. The hack is very much arched, compressed, thin along the dorsal line, as iu 

 the other species of the genus with which we are acquainted. The greatest depth of the body, 

 taken under the first dorsal fin, is very nearly equal to the third of he total length. 



Tlie origin of the first dorsal fin is situated somewhat in advance of the base of the pectorals. 

 It is composed of more slender rays than in A. grunniens and A. concinnus. Its outline is more 

 of a subtriangular shape, since the second and third rays are shorter than the fourth, which is 

 the highest ; the others diminish again gradually, the first ray being, as usual, reduced to a 

 email conical spine. The shape of the second dorsal does not diifer from that of the other 

 species. The caudal enters a little over five times and a half in the total length ; its posterior 

 margin is nearly rectilinear, instead of being convex, as in A. grunniens and A. concinnus. 

 The origin of the anal is situated opposite the middle of the second dorsal ; its first spine is 

 exiguous ; the second is very stout, and nearly as deep as the second articulated ray. The tip 

 of the first ray extends beyond a vertical line, which would intersect the terminus of the base 

 of the second dorsal. The ventrals and pectorals are but moderately developed. A considerable 

 space is left between the extremities of the ventrals and the vent, which is situated somewhat 

 in advance of the anterior margin of the anal. 



Br. V : V ; D X, I, 28 ; A II, T ; C 5, 1, 8, T, 1, 4 ; V I, 5 ; P 18. 



The ground color of the upper regions, as exhibited upon specimens preserved in alcohol, is 

 purplish brown, whilst the inferior regions are greyish or yellowish. On the centre of each 

 scale exists a dark purplish spot, which, being sometimes confluent with the adjoining spots of 

 the same row of scales, may constitute narrow streaks, corresponding to the series of scales. 



