REPORT ON IOBTHYOLOGY. 427 



The branchiostegal bones appear to amount to twelve on each side; the two 

 internal are wide and compressed and much larger than the others. The branchiostegal 

 membrane is deeply, and when not extended appears to be acutely, emarginated, the 

 emargination extending to the vertical of the posterior border of the eye. The mem- 

 brane is attached to the throat to within a short distance of the bottom of the emargina- 

 tion. The mental fold is considerably nearer the latter than the jaw. 



The dorsal fin commences at three-tenths of the length from the snout over the 

 posterior half of the interval between the bases of the pectorals and ventrals. Its 

 base is equal to about a twelfth of the fish's length, and equals four sevenths of the 

 greatest height. The spinous ray is moderate, and not more than half as long as the 

 second articulated or longest ray; it is entirely enveloped in the skin, and no serratures 

 can be perceived; the skin in which the spine is imbedded is considerably prolonged, 

 compressed, and obliquely rayed or striated. 



The adipose fin is elongated, subrhomboidal, advancing slowly outward and 

 backward, very thick at the base, and compressed toward the margin, which is some- 

 times jagged; it is situated over the last two-thirds of the anal fin, and eoterminal 

 with it. 



The anal fin commences at nearly six tenths of the distance between the snouj 

 and caudal margin; its length is almost equal to a tenth of the same, and its greatest 

 height to a ninth. The rays rapidly increase in length to the middle ones, which are 

 longest. The rays, especially anteriorly and at the base, are enveloped in a thick 

 fat skin. 



The pectorals are situated immediately behind the descending opercular margin 

 at less than a quarter of the length. When open, they are horizontal. The four, or 

 longest rays, inclusive of the membranous termination of the spinous one, are nearly 

 equal to a seventh of the entire length. The compressed spine is about half as long- 

 as the succeeding rays, and is anteriorly provided with ridges rather than teeth, and 

 posteriorly with tubercular teeth. The membrane continued from it is eoterminal with 

 the three succeeding rays, and is striated obliquely forward and interiorly. 



The ventral fins commence at the fourth tenth of the length; their bases, if con- 

 tinued backward, would intersect each other at right angles, but the distance by which 

 they are separated behind is nearly equal to their base. Their margins are rounded, 

 and the longest rays are about an eleventh of the length. They cease some distance 

 before the anal fin. 



The anus is situated between the ventrals, at a distance in advance of the anal 

 fin equal to a twelfth of the total length; its margin is radiated by ridges. The genital 

 papilla is small and behind. 



The caudal fin is scarcely emarginate, and has a straight base; the shortest rays 

 form fifteen hundredths of the total length, and the longest equal sixteen hundredths. 

 Numerous simple rays, enveloped in a very fat skin, are continued on the superior and 

 inferior faces of the peduncle. 



The radial formula may be expressed as follows: 



D. I. 5. 4; A. 2. 12. 4; C. 20. 1. 7. 8. 1. 10; P. 1. 9; V. 1. 8. 



