1566 Bulletin 4.7, United States National Museum. 



a. Vertical fins not elevated ; caudal simply lunate ; color brownish, with blue shades 

 above, the lower half more or less abruptly yellow ; each scale with a blue dot ; a 

 black spot on back of caudal peduncle; nostril large, eye in adult. 



BAIRDII, 1979. 

 aa. Vertical fins much elevated; caudal lobes falcate. 



b. Caudal' fin golden yellow or orange in life; body dark brown with round spots 

 of deep blue on head, nape, and sometimes on back. CHRYSURUS, 1980. 

 bb. Caudal fin dark, like the body, not yellow. 



c. Body dark, sprinkled with blue spots like flakes of snow. 



NIVEATUS, 1981. 



cc. Body not covered with blue spots ; nostril a small pore ; vertical fins 

 falcate ; vertical fins deep blue without pale edgings ; body deep blue, 

 with 3 large, round, sky-blue spots above lateral line, 1 near its front, 

 1 under front of spinous dorsal, 1 under last spine ; a blue saddle 

 behind last dorsal ray these distinct at all ages; head with blue 

 streaks and spots. DORSALIS, 1982. 



1979. MICROSPATHODON BAIRDII (Gill). 



Head 3; depth If. D. XII, 16; A. II, 14; scales 3-29-10. Body short, 

 compressed, elongated; nape abruptly produced behind and above a 

 depression which lies above the eye, the nape thus projecting forward in 

 a fleshy crest; anterior profile steep, with fleshy corrugations, separated 

 by depressions; tip of snout above premaxillary enlarged to a fleshy pad 

 under which the jaw slips, separated from preorbital and top of head by 

 a deep crease, deeper in larger specimens. Nostril midway between eye 

 and crest, its size much larger than in M. dorsalis, being J diameter of 

 eye. In M. dorsalis of the same size the nostril is reduced to a small pore, 

 about -J- of eye. Preorbital lower than in dor sails, its height 2f in head in 

 adult; in dorsalis of the same size the preorbital is 2 in head. Teeth 

 small, truncate, movable, about as in dorsalis; lower jaw shorter; width 

 of mouth 2 in head; 4 or 5 rows of scales on cheek. Caudal peduncle 

 short and deep, length 2 in head, its depth 2 in head; dorsal elevated but 

 not falcate, simply angular, its longest ray 1 in head; anal similar, its 

 longest ray 1| in head; caudal lunate, its lobes not produced, the upper 

 longer, 1 in head; pectoral 1J in head; ventral 1-J- in head. Color uni- 

 form deep blueblack without paler margins to fins except very narrow 

 line on upper ray of pectoral and upper lobe of caudal; no spots. This 

 species is well separated from M. dorsalis, differing in the much larger 

 nostril, fleshy hump at nape, in the lower preorbital and in the uneven 

 slope of profile, as well as the absence of falcate tips to fins. Here described 

 from adult examples 6 to 12 inches long from Clarion Island (collected 

 by McGregor). The very small specimens which have been named Micro- 

 spathodon lairdii seem to be the young, having the large nostril and the 

 non-falcate fins. The bright orange markings seem to disappear with 

 advanced age. 



The color of the young is thus described by Dr. Gill : 



"The color in extreme youth, as represented by a specimen 10 lines long, 

 is greenish yellow, modified by blue above on the middle of each scale, 

 the margins alone being brownish; below a line drawn from the axil of 

 the pectoral to that of the dorsal fin, the blue has disappeared, and the 



