I ^ PAPERS FROM TORTUGAS LABORATORY vol. xxxiv 



Archosargus probatocephalus (Walbaum). Sheepshead 



This species is not mentioned in Dr. Longley's notes as occurring in the Tor- 

 tugas. Therefore, he evidently did not observe it there, and Jordan and Thomp- 

 son (Bull. U. S. Bur. Fish., vol. 24, 1904 (1905), p. 243) apparently did not have 

 specimens from Tortugas, as they merely stated, "Reported to occur." 



As this sheepshead is taken at Key West, though not common there, it might 

 be expected at Tortugas. Its relative Archosargus unimaculatus (Bloch) is more 

 commonly taken at Key West. Therefore, this species, too, may be expected in 

 the Tortugas. 



Texas to Cape Cod, rarely straying as far as Bay of Fundy. S. F. H. 



Family KYPHOSIDAE. Rudder Fishes 



Kyphosus Lacepede, 1802 



The distinguishing characters of the two local species of rudder fish may be 

 most conveniently set forth in a key. S. F. H. 



Key to the Species 



a. Depth 2.1 to 2.3; scales 55 to 57 (counted below lateral line); D. 

 XL12V2, sometimes Xl,i^Y 2 \ A. III,nJ4, sometimes III,i2 1 / 2 ; gill 

 rakers 16 to 18; yellow streaks along rows of scales, if present, 



scarcely darker than straw yellow sectatrix 



aa. Depth 2.3 to 2.6; scales 62 to 65 (counted below lateral line); D. 

 XI,i4 L 2, sometimes XL13V2; A. Ill, 13V2, occasionally 111,12%; gill 

 rakers about 22; yellow streaks along rows of scales brassy yellow . . . incisor 



Kyphosus sectatrix (Linnaeus). White chub 



Perca sectatrix Linnaeus, Syst. nat., 12th ed., 1766, p. 486 — Carolinas (a correction, mis- 

 printed soltatrix in 10th ed.). 



Kyphosus metzelaari Jordan and Evermann, Proc. Calif. Acad. Sci., ser. 4, vol. 16, 1927,, 

 p. 506 — Curacao; Venezuela. 



Only an evidently unfinished account has been found. The following is com- 

 piled from it and from field notes and a table of measurements and counts. 



The schooling places of this fish differ from those of Kyphosus incisor, being 

 found along ledges of beach rock off Loggerhead Key, about the Laboratory 

 wharf, in and about the large coral stacks off Bird Key, and around the Palythoa- 

 covered ledges off Bush Key. 



It is chiefly if not wholly herbivorous, feeding on the bottom and on floating 

 Sargassum. 



In shade it is changeable, being darker under corals and gorgonians than when 

 resting in the open. It sometimes displays a checkered pattern like the yellow 

 chub. A fresh specimen 143 mm. long is described in field notes as follows: 

 "Coloration paler than incisor, with a yellow horizontal line from upper tip of 

 maxillary nearly to margin of preopercle; yellow lines on sides between rows of 

 scales not quite as wide as interspaces; a white line across nape; a yellow spot 



