!8a PAPERS FROM TORTUGAS LABORATORY vol. xxxiv 



Chaetodon mauritii Bloch, ibid., p. 109, pi. 213, fig. 1 — Brazil (after a drawing by Prince 



Maurice). 

 Chaetodon sargoides Lacepede, Hist. nat. poiss., vol. 4, 1803, pp. 471, 473, 543 — Martinique. 

 Glyphisodon moucharra Lacepede (part) , ibid., p. 543 — Brazil. 



This fish some recent authors have called Abtidefduf marginatus, on the 

 ground that the older name A. saxatilis belongs to an Asiatic species. In support 

 of this view Linnaeus himself may be cited. In the Systema naturae, 10th edition 

 (1758, p. 276) he noted his earliest mention of the species. At the same time he 

 referred to synonymy Spams fasciis qviinque (Balk, in Linnaeus, Amoen., vol. 1, 

 1749, p. 312), also described without locality, and for the first time stated that the 

 habitat is India. That this is not necessarily true would appear, however, from 

 the fact that on the facing page he made the same statement regarding the Amer- 

 ican Chaetodon lanceolatus, now Eques lanceolatus. The critical reference is in 

 the Systema naturae, 12th edition (1766, p. 466), where eight years later he ex- 

 tended his synonymy and observed that the species came from Brazil. He was 

 aware that in the meantime Gronovius in the Zoophylacium (1763, p. 64) had 

 identified Chaetodon saxatilis with the faguacaguare of Marcgrave and of Piso; 

 Linnaeus approved this finding, and admitted his earlier error. W. H. L. 



I strongly suspect that some of Dr. Longley's manuscript on this species was 

 lost. All that I received is the foregoing. The following remarks were compiled 

 from his field data : 



This is a common fish found among the coral heads about the local keys, and 

 also in some of the deeper holes in 15 feet or more of water. It does not stay as 

 near the bottom as A. taunts; it often swims high and at least once was seen 

 breaking the surface. 



Its food, according to 3 stomachs examined, consists largely of algae, mixed 

 with some copepods. One had eaten a pelagic fish egg. 



The fish commonly are seen in two color phases, a light and a dark. The light 

 phase was observed when the fish were feeding over light sandy bottom, or when 

 swimming high above coral heads. The fish showed the dark phase when among 

 dark crevices among corals, and especially when in deep water. The light phase 

 is light gray; head slaty with greenish tinge; body with five dark vertical bands 

 on sides; upper third of body yellowish; soft dorsal, caudal, and anal dusky. In 

 some individuals the suborbital region may be yellowish, giving the effect of a 

 light spot. In the dark phase the fish is blue to slate gray, with all fins, except 

 pectorals, slaty; five vertical bands slaty black. A few large individuals observed 

 in water 10 to 12 feet deep, in crevices, were so dark that the bands were scarcely 

 visible. 



The fish can pass almost instantaneously from one phase to the other. Those 

 swimming near the surface showed the maximum of yellow. A fish kept in a 

 tank became quite yellow when excited, as when an attempt was made to catch 

 it. When left at rest, it again became darker. 



Spawning was observed repeatedly. The breeding season extends at least 

 through June, July, and August. The eggs are attached in a single layer by 



