320 PROCEEDINGS OF THE ACADEMY OF [June, 



process of maxillary extending to a vertical through posterior border of 

 eye; maxillary with a leaf -like flap a fourth of its length longer than 

 diameter of eye, and with branched striations radiating from its point 

 of attachment; opercular bones conspicuously striated. Teeth weak; 

 loosely attached ones on vomer, a row of 4 on maxillary, and 4 on each 

 side of symphysis of lower jaw, the posterior of which is 2 times the 

 length of the anterior. Gill-rakers on first arch 5 -f- 10, provided with 

 tooth-like setse on the inner side; filaments of pseud obranchise equal in 

 length to those of gills. 



Origin of dorsal above upper edge of gill-opening, the rays highest 

 near beginning of posterior third of body where they are about l-J 

 times the diameter of eye; anterior rays not separated from the pos- 

 terior ones nor lengthened. Length of pectoral slightly more than 

 diameter of orbit. A'^entral fins absent, or possibly represented by a 

 mere filament, the place of insertion indicated by a spot on the breast 

 below base of pectoral, where the skin, colored and sculptured, looks 

 much like a pair of folded fins. Caudal projecting upwards; short 

 fragmentar}'- filaments present; several small spines projecting down- 

 wards and backwards from the broadened end of the caudal peduncle. 



Head naked; scales of body in the form of minute pads or plates 

 containing a varying amount of bony matter; those on median ventral 

 surface pointed, hard and white like enamel, covering a narrow ridge 

 and lying in a single row near extremity of tail; among those on dorsal 

 part of body, some are enlarged and arranged in vertical rows parallel 

 with the interneurals. Lateral line with small, quill-like tubes; 

 beginning at upper edge of gill-opening, bending rather abruptly 

 downwards and extending along body somewhat below the median 

 line; not armed at any point. 



Color bright silvery. 



Type No. 13,080 Stanford University collection. 



Called seleniris on account of a fancied resemblance of the long, 

 flat, silvery body to the colorless lunar rainbow. 



