Smithsonian miscellaneous collections . wise widely divergent in the schemeof classification. In specimens examined of Pontinus rathhitni, Scorpaena cakarata,and S. agassisi, 18-22 mm., the third anal spine is as in the adult. is a smaller species than longispinis and this developmentalchange probably occurs at a smaller size. In the species of Scorpaena,on the other hand, it is possible that the third anal spine is as in theadult to begin with. Pectoral fin.—The pectoral shape differs with the genus to a certainextent, although this character is not altogether stable because of the
Smithsonian miscellaneous collections . wise widely divergent in the schemeof classification. In specimens examined of Pontinus rathhitni, Scorpaena cakarata,and S. agassisi, 18-22 mm., the third anal spine is as in the adult. is a smaller species than longispinis and this developmentalchange probably occurs at a smaller size. In the species of Scorpaena,on the other hand, it is possible that the third anal spine is as in theadult to begin with. Pectoral fin.—The pectoral shape differs with the genus to a certainextent, although this character is not altogether stable because of theirregularity in the relative contraction or expansion of the interradialmembrane in preserved specimens, which influences the shape of the 1 Numbers of specimens examined are U. S. National Museum catalog num-bers unless otherwise indicated. NO. 8 WESTERN ATLANTIC SCORPIONFISHES—GINSBURG 13 fin. Nevertheless, allowing for this difficulty of the subject matter andfor a considerable latitude in accounting for specific differences and. Fig. 4.—Pectoral fins of four scorpaenid species. The shape of the pectoral finis generic to some extent, a, Pontinus longispinis; b, Helicolcnus niaderensis;c, Trachyscorpia crishdata; d, Scorpoena grandicornis. Drawn by Mildred intraspecific variability, this character still has some generic pectorals of four genera are illustrated in figure 4. One genus, Pontinus, is separable from the others here treated byhaving all the pectoral rays unbranched. The number of pectoral rays 14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 121 is, on the whole, of considerable importance as a specific character(table 2), although related species often overlap in this count. Scales.—The structure of the scales, cycloid or ctenoid, appearsto be of considerable value as a generic character and it is here soused. This character was inadequately treated heretofore. Jordan andEvermann (1898, p. 1759), in their key to the genera, use the str
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