i94i CATALOGUE OF FISHES OF TORTUGAS ^y 



The eggs are almost perfectly ellipsoidal. Laid end to end, 10 in a row, they 

 measure 6.0 mm., and 10 laid side by side measure 4.5 mm. The egg envelope is 

 transparent, is attached to the substratum by a tuft of a few long, delicate fila- 

 ments grouped in a small area at one pole, and has a single large oil globule in 

 its straw-colored yolk. 



West Indies to Florida. W. H. L. 



Pomacentrus Lacepede, 1803 



There has been, and apparently still is, uncertainty concerning the relationship 

 of the species of this genus. Bewilderment has been expressed by several investi- 

 gators. Parr (Bull. Bingham Oceanog. Coll., vol. 3, art. 4, 1930, pp. 67-84) took 

 cognizance of this confusion, and made an extensive study of a considerable 

 number of specimens available to him. He came to the conclusion that plamfrons 

 and partitus were of specific rank. As for the rest of his material, he was unable 

 to arrive at a definite conclusion. 



Dr. Longley, too, took cognizance of the inadequate knowledge of this group 

 of fishes, and accordingly made careful field observations, and examined many 

 specimens in American and European museums, with a view to discovering dis- 

 tinctive structures, color, and habits. The result was that he recognized four or 

 five species in the Tortugas fauna. These include the two, planijrons and partitus, 

 also recognized by Parr, and two others, leucostictus and adustus. Apparently he 

 recognized a fifth one, xanthurus, which he mentioned a few times in connection 

 with other local species in the accounts that follow. He prepared no discussion, 

 however, and has no notes under that name. In his copy of Jordan, Evermann, 

 and Clark's Cheeky list, wherein (p. 413) this name is in the synonymy of leuco- 

 stictus, he has the marginal note in regard to xanthurus, "A good species," and he 

 has given it a serial number, as his custom was for species occurring at Tortugas. 



Though Dr. Longley took a few names out of synonymy, he also placed several 

 others in synonymy, for which he stated his reasons. The conclusions given may 

 not have been considered final by him. They seem well worthy of consideration, 

 however, as it seems certain that headway toward a better understanding of the 

 local species of this group has been made. 



The following note was found among Dr. Longley's papers: "The difficulty 

 that students have experienced is largely due to the fact that some of the species 

 change greatly in appearance with age, that individuals display temporary 

 changes in coloration, and finally that in one species at least sexual dimorphism 

 in color occurs." 



Many specimens are included in the Tortugas collection, all of which, exclusive 

 of one specimen of partitus, reached me without labels. As the specimens have 

 faded, I have found it very difficult to identify some of them, even with Dr. 

 Longley's discussions before me. "Extremes" are not especially difficult to iden- 

 tify, but "intermediates" are included that caused trouble. 



I am not certain enough of the specific differences to offer a key. I believe that 

 the number of pectoral rays usually will distinguish adustus from the other local 

 species. In 17 specimens that appeared definitely to be of this species by the depth 



