496 APPENDIX. 



The narrow, slightly pitted, scaleless disk of the preopercu- 

 lum bounds the scaly cheek behind and below, and has an 

 entire edge with neither spine nor acute angle at the bend. 

 The other pieces of the gill cover are closely covered -with 

 scales, only a little smaller than those of the body. The pretty- 

 wide thin inter-operculum lays freely over the gill membranes, 

 and covers them when shut up. The sub-operculum is minutely 

 crenulated on the edge, and has a small sub-membranous tip, 

 which projects a little beyond the three opercular teeth. A 

 small curved notch marks the separation between the inter- 

 operculum and sub-operculum. 



The scales extend on the crown of the head to the middle 

 of the orbiti. The snout, lips, jaws, the place at the corner of 

 the mouth over which the maxillary glides and the gill mem- 

 brane are scaleless. The scales of the body are very regularly 

 disposed, shewing rhomboidal disks v,'hen in situ, with strongly 

 ciliated edges. The lateral line ascends at its commencement 

 and bends rather suddenly under the first soft dorsal ray to 

 run near and parallel to the ridge of the back. It terminates 

 beneath the sixth ray from the end of the fin, but recommences 

 on the fourth scale beneath, and runs in the middle height of 

 the tail to the base of the caudal. Two or three of the scales 

 before its recommencement, have a minute pit in the middle of 

 their disks, as is not unusual with the Glijphisodomi. The first 

 part of the lateral line forms an almost continuous tubular ridge 

 traced on thirty-eight scales of the second row from the 

 summit of the back; the posterior part traverses six or seven 

 scales. There are twelve or thirteen scales in a vertical row 

 on the side of the body. 



The anus, situated a short way before the anal fin, has a 

 very small aperture. 



There are no scales on the fin membranes. The three dorsal 

 spines are short, graduated, moderately stout, and pungent. 

 The twenty-three soft rays are all distinctly articulated, and 

 more or less branched. The last ray is divided to the base, 

 and is graduated with the two preceding ones, giving a rounded 



