j 9 5 PAPERS FROM TORTUGAS LABORATORY vol. xxxiv 



series of pale bars of the approximate width of eye, the first running obliquely 

 from just before dorsal origin to pectoral axil; the sixth under end of dorsal base, 

 and an additional one before base of caudal; a small dark spot of size of pupil 

 above lateral line at base of caudal. W. H. L. 



Two specimens, 105 and in mm. long, are included in the collection. These 

 are brownish, with lower parts of head, chest, and abdomen pale, and lower half 

 of opercle and chest nearly white; blue spots on rows of scales below lateral line 

 now pale. The specimens have no definite black spots (not even the one on base 

 of caudal mentioned in the specimen described by Dr. Longley), wherein they 

 differ from those of poeyi. 



The scales in advance of dorsal, unlike those of poeyi, are considerably reduced 

 in size, there being seven or eight oblique rows next to mid-line of nape. Two 

 canines in upper jaw anteriorly and 4 in lower jaw. 



The following proportions and enumerations are based on the 2 specimens in 

 the collection: Head (without opercular lobe) 3.7, 3.7; depth 4.05, 4.25. Eye in 

 head 4.8, 4.8; snout 2.6, 2.7; interorbital 7.5, 7.5; caudal peduncle 2.0, 2.15; ventral 

 1.85, 2.0; pectoral 1.5, 1.5. D. IX,n, IX,n; A. III,i2, III,i2; P. 11, 12; scales 3-27-8, 

 3-26-7, before dorsal 7, 8. 



West Indies to Florida. S. F. H. 



Thalassoma bifasciatum (Bloch) 



(Plate 26, figure 1) 



Labrus bifasciatus Bloch, Naturgesch. ausland. Fische, vol. 5, 1791, p. 131 — West Indies. 

 fulis nitida Giinther, Cat. fish. Brit. Mus., vol. 4, 1862, p. 190 — Jamaica. 

 fulis nitidissima Goode, Amer. Jour. Sci. and Arts, ser. 3, vol. 14, 1877, p. 293 — Bermuda. 

 Bermudichthys subfurcatus Nichols, Proc. Biol. Soc. Washington, vol. 33, 1920, p. 62 — 

 Bermuda. 



The forms here synonymized have been a source of much difficulty to ichthy- 

 ologists. The first three names were perhaps for the first time regarded as equiv- 

 alent in my report in Carnegie Institution of Washington Year Boo\ Nos. 13 

 (1914, p. 208) and 14 (1915, p. 208). 



The conclusion reached rests on observation of fish in the field. Thalassoma 

 nitidum and T. nitidissimum there underwent changes in color in which from 

 moment to moment under changing conditions either phase replaced the other. 

 The two occurred together with every intermediate color phase connecting them. 

 The scale counts were identical, and the difference in the form of the caudal was 

 traceable through every intermediate stage in the elongation of the outer rays. 

 Five years later, however, having in the meantime become aware that the nitidum 

 form is often much larger than the smallest bifasciatum, in the series of reports 

 mentioned I expressed doubt regarding the correctness of my earlier judgment. 

 Later C. M. Breder (Bull. Bingham Oceanog. Coll., vol. 1, art. 1, 1927, p. 60), 

 after careful study of growth changes in material available to him, expressed the 

 opinion that nitidum would eventually be synonymized with bifasciatum, but 

 did not effect the reduction. Beebe and Tee-Van noted that 6 Haitian specimens 



