32 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



scombrid characters (Matsubara and Iwai, 1958) that its transfer to 

 the family Scombridae has been advocated. Conversely, the scombrid 

 Grammatorcynus has a number of gempylid characters (Matsubara 

 and Iwai, 1958). Finally, it seems that, except in a few characters, 

 the genus Scombrolabrax (fig. 6), could serve morphologically as 

 an ancestral form for the trichiuroids and, in most respects, for the 

 Scombridae as well. 



Figure 6. — Scombrolabrax heterolepis: sketch to show external appearance, based on speci- 

 men 5}i inches SL (USNM 197651) taken off Mississippi delta by the "Oregon" (drawn 

 by Barbara Downs). 



Regarding scombrid phylogeny, Kishinouye (1923) considered 

 certain of the tunas to be so specialized as to warrant a separate order, 

 Plecostei. This classification, though adopted by Berg (1940), was 

 shown long ago to be based on inadequate grounds (Takahasi, 1926). 



At the base of the scombrid series, Fraser-Brunner (1950) placed 

 Gasterochisma. It appears to me, however, that Gasterochisma, which 

 I have examined only superficially, bears at least as much resemblance 

 to the Bramidae as to the Scombridae; if Gasterochisma is a scombrid 

 at all, it is at best a highly aberrant one. 



Starks (1910) seems to have been correct in considering Scomber 

 as the least specialized living scombrid. Among the percoid-like 

 characters retained by Scomber but lost by most or all of the rest of 

 the Scombridae are the following: 



Mesethmoid with a low median crest anterodorsally (see Allis, 

 1903, pi. 4: fig. 5). Intercalar not expanded on the posterodorsal face 

 of the skull, not separating the exoccipital form the pterotic; lower 

 limb of the posttemporal articulating with an intercalar projection 

 that extends downward and backward from the ventral cranial sur- 

 face. Premaxillaries with separate articular and ascending processes, 

 the latter not greatly expanded (ibid., pi. 5: fig. 16). Circumorbital 

 series of bones complete (ibid., pi. 3: fig. 4). Operculum without a 

 smoothly rounded free border but rather with a moderately deep 

 indention above (ibid., pi. 3: fig. 4). An anal spine present (Matsui, 



