29 



backward to the end of the tail. The anterior basal portion only of the anal fin is preserved, 

 and the position of the dorsal fin is indicated, but the specimen is elongated by distortion, and 

 both fins are more distant from the tail than they otherwise would be. The general contour of 

 the specimen is much the same as that of others in the collections of the Geological Survey 

 similariy distorted, and the characters of the scales are cleariy those of E. brovmi, to which 

 species the specimen is referred. 



Elonichthys ellsi, Sp. nov. 

 Plate X, figs. 1-6. 



A spocies of rather small size. Greatest depth a little less than one-fourth the length. 

 Head, with opercular apparatus, one-fourth the total length. Dorsal fin large, arising very 

 slightly behind the mid-length of the fish, and but little in advance of the anal fin, which is about 

 the size of the dorsal. Both of these fins are triangular, with a base about equal to the length of 

 the anterior border. Fulcra are apparently present on all the fins. They are seen plainly on 

 the dorsal and anal fins. Of the ventral and pectoral fins, a few rays only are preserved, which 

 serve as an index to the fins' position. Ventral fins rather closer to the anal than to the pectoral 

 fins. The fin rays are articulated, except the principal ones of the pectoral fins, which are 

 entire, at least, proximally; they are finely striated in the direction of their length, plate X, 

 fig. 6. The tail is deeply forked. Scales of moderate size; about as deep as broad on the flank 

 anteriorly, where they are ornamented with nine or ten conspicuous, narrow ridges, directed 

 backward and deeply serrating the posterior border. Posterior flank scales less highly ornate, 

 and with few, but well marked serrations on the posterior margin. Scales of the caudal body 

 prolongation nearly smooth. Enlarged scales extend along the dorsal ridge in a row, in advaince 

 of the dorsal fin, to the head, and behind the same fin backward to the termination of the upper 

 lobe of the tail. Similarly enlarged scales occur between the anal fin and the lower lobe of the 

 tail, with a few, probably three or four, in front of the anal fin. Head-bones marked by ir- 

 regular, short ridges, and tubercles. Suspensorium apparently oblique. 



The ridges of enamel on the anterior flank scales, plate X, fig. 2, constitute the most con- 

 spicuous feature of the scale ornamentation of this species. These ridges, nine or ten in number, 

 are mainly developed on the posterior half of the scale, and have a general direction backward 

 and slightly downward, more rarely pointing horizontally backward in the upper portion of the 

 scale, or even obliquely upward near the upper margin. When closely examined, the ridges are 

 seen to be depressed at regular intervals, and thus have somewhat the appearance of rows of 

 connected tubercules. In the anterior half of the scale they are represented only by 5 or 6 ill- 

 defined ridges, having the same oblique direction. A few fine strige occur near and parallel to 

 the lower margin. The conspicuous serration of the posterior margin is due to the projecting 

 ends of the enamel ridges. In the posterior flank scales, plate X, fig. 3, there are only three or 

 four serrations in the back margin; the finer striations parallel to the lower margin persist, but 

 m the upper part of the scale surface two or three oblique striations alone remain. The diamond 

 shaped scales of the upper caudal lobe are generally marked by a longitudinal depression in their 

 otherwise plane service. 



