1941 CATALOGUE OF FISHES OF TORTUGAS I2g 



distinct power to change shade, as is apparent when it passes from over corals to 

 lighter bare bottom. 

 Brazil to Florida. W. H. L. 



Anisotremus virginicus (Linnaeus). Porkfish 



(Plate 2, figure 3; plate 16, figure 2) 



Spams virginicus Linnaeus, Syst. nat., 10th ed., 1758, p. 281 — South America. 

 Pristipoma spleniatum Poey, Memorias, vol. 2, i860, p. 187 — Havana. 



Rather uncommon. Found particularly about the coral stacks or other offshore 

 haunts. 



Stomachs of 6 individuals, taken at daybreak, were filled with ophiurans, mol- 

 lusk shells, annelids, and fragments of crustaceans. Another taken before 9:00 

 a.m. contained a small fish and an annelid. On the contrary, 2 taken at 5:00 p.m. 

 were empty, and no adults have been observed feeding by day, so it may be 

 inferred that feeding occurs at night. 



In an apparent feeding habit the young up to an estimated length of 150 mm. 

 differ from adults. The smaller ones in particular are often seen nibbling and 

 pecking at the surfaces of larger fishes, such as Sphyraena barracuda, Kyphosus 

 incisor. Lutianits griseus, and Caranx ruber, presumably removing ectoparasites 

 from the skins of their hosts, but the stomach of an individual examined yielded 

 nothing I recognized as belonging to parasitic species. 



Young fish show a color pattern different from that of the adult. They are 

 yellow over the head and back and grow grayer below. On the side are two dark 

 longitudinal stripes, the upper at a level higher than eye and running concur- 

 rently with base of dorsal, the lower passing through eye to base of caudal, end- 

 ing in a black dumbbell-shaped spot. It was to such young fish as these that Poey 

 gave the name Pristipoma spleniatum. 



In fish 75 mm. long, the adult coloration is sometimes developed. The pattern 

 is shown in plate 16, figure 2. The longitudinal dark stripes have become rather 

 vivid yellow; fins yellow; the light interspaces between yellow lines blue; two 

 bands on the head black; ocular bar of the width of pupil, the part of the iris 

 before and behind it being yellow like the rest of the head. 



This is one of the species illustrated in reproductions from autochrome photo- 

 graphs in the National Geographic Magazine, volume 51, January 1927. The 

 plate (XIII) showing it has been retouched, by someone who clearly did not 

 know this fish in the flesh. The ocular black stripe so effectively concealed the 

 eye that the plate was regarded as defective, and the little yellow, which is all 

 that really shows in advance of the black band through the eye, has been ex- 

 tended slightly and a supernumerary eye painted in. 



Brazil to Florida. W. H. L. 



Anisotremus surinamensis (Bloch) 



Only a few very large individuals and a single smaller one were seen. The 

 large ones were observed about the greatest coral heads. The smaller fish was at 

 the rocky shore north of the east lighthouse dock. 



