n8 PAPERS FROM TORTUGAS LABORATORY vol. xxxiv 



the mark which has long distinguished the unpalatable ones, are usually eaten. 

 But the effect of experience appears in the fact that striped fresh fishes [the mark 

 that had been used for preserved fish] in my tests were rejected with twice the 

 frequency of banded fresh ones. Striped fresh fishes, when taken, were taken too 

 with greater hesitation than banded ones, and preserved striped fishes were re- 

 jected to the end very much more commonly than banded preserved ones. As a 

 matter of fact, the latter are almost always seized before being rejected, whereas 

 a large part of the former are allowed to sink to the bottom untouched. There 

 seems, therefore, no reason to doubt that the gray snapper can discriminate be- 

 tween such simple patterns as those mentioned, and is able to form associations 

 between either and the palatability or unpalatability of the food-fish display- 

 ing it." 



Atlantic coast of tropical America, sometimes straying northward as far as 

 Cape Cod. S. F. H. 



Lutianus apodus (Walbaum). Schoolmaster 



(Plate 9, figure 2; plate 24, figure 2) 



No account of this species was found among Dr. Longley's manuscripts. It is 

 evident from his field notes that, next to Lutianus griseus, it is the most abundant 

 snapper in the vicinity. Evidently it occupies about the same ground as L. griseus 

 during daylight, as Dr. Longley's notes show that it was taken several times with 

 that species in a single dynamite blast. At night, when feeding occurs, the fish 

 seem to separate. 



Records of the examination of 241 stomachs for food were found in Dr. 

 Longley's notes. The three principal foods consisted of crabs, shrimps, and small 

 fish, named in the order of their apparent importance, the fish being notably less 

 numerous than crabs and shrimps. Among these foods, as far as they were recog- 

 nizable, Dr. Longley listed most frequently the following: spider crabs 

 (Mithrax), porcelain crabs (Porcellana and Petrolisthes), snapping shrimps 

 {Crangon and Alpheus), and parrot fishes (Labridae and Scaridae). Foods of 

 other groups were comparatively unimportant, except palolo 1 (a segmented 

 worm) for a few days. Fragments of octopus appeared six times, worms (other 

 than palolo) twice, clam once, isopod once, amphipod once, and Dictyota frag- 

 ments three times (the last possibly taken incidentally in the capture of crabs 

 and shrimps). 



Though this species and the gray snapper occupy about the same grounds dur- 

 ing the day, as already stated, they seem to feed separately on different grounds 

 at night. For a comparison of the food of the two see the papers cited in the 

 account of the gray snapper. 



Schoolmasters seem to occur in nature in two color phases, designated as "pale 

 yellow" and "banded." On a specimen 30 mm. long Dr. Longley has the follow- 



1 The reason for the occurrence of palolo worms for only a few days is explained in Dr. 

 Longley's article entitled "Life on a coral reef" (Nat. Geog. Mag., vol. 51, 1927, p. 69); also 

 in Carnegie Inst. Wash. Year Book No. 22 (1923), pp. 159-160; and by Caswell Grave in 

 Carnegie Inst. Wash. Year Book No. 24 (1925), p. 227. 



