no. 3647 PERCIFORM FISHES — GOSLINE 7 



One is logical consistency. The callionymoids are a case in point. 

 I believe that the callionymoids, like the gobiesocids, are notothe- 

 nioid derivatives. Thus, unlike the other suborders recognized herein, 

 the callionymoids would seem to be derivatives of derivatives of the 

 percoids. To be consistent, therefore, they should not be placed in 

 parallel with the other suborders recognized here but either should 

 be included in the notothenioids or be removed from the Perciformes 

 entirely. Of these alternatives, I prefer the latter. From the point 

 of view of classification, the callionymoids then would have a position 

 analagous to that of the Tetraodontiformes (which seem to have 

 arisen from the percoid suborder Acanthuroidei) . 



In general, recognition of a group as a separate superfamily, sub- 

 order, or order is based on degree of morphological differentiation, 

 precedent, and the size of the group under consideration. As to the 

 last factor, the generally accepted dictum "that the size of the gap 

 [between units] be in inverse relation to the size of the unit" (Mayr, 

 1943, p. 139) has been adopted. Thus, the large group Scorpaeni- 

 formes is considered herein a separate order from the Perciformes, 

 though the known differences between the two units are not great 

 (cf. Berg, 1940; Matsubara, 1953). Conversely, though the above 

 dictum militates against small units, the complete elimination of 

 certain small perciform suborders does not appear feasible at the 

 present time. Thus, to combine the Kurtoidei, containing but a single 

 genus, with any other perciform suborder would seem to abrogate 

 phylogenetic principles. The same is true of the Schindlerioidei. 

 Again, I have come to the somewhat reluctant conclusion that the 

 Istiophoridae, Xiphiidae, and Luvaridae bear no real relationship 

 to the scombrid fishes and must, at least provisionally, be placed 

 in a separate suborder by themselves (see p. 28). 



Finally, there arises the question of how to draw the line XY 

 in figure la. One could draw such a line with a view to creating a 

 definable basal suborder Percoidei. This would leave bits and pieces 

 of radiating lineages outside the line XY to be tucked away in one 

 suborder or another as decorously as possible. In practice, the line 

 XY has been drawn with an eye to creating coherent derivative 

 suborders. In figure la, therefore, XY should have been drawn as 

 a zigzag line, dipping more or less deeply into the basal Percoidei 

 at different points. In practice, then, the Percoidei contains all those 

 perciform fishes that do not belong to some other suborder. The 

 Percoidei presumably contain related fishes, but defining it morpho- 

 logically in positive terms is difficult. 



With regard to the derivative suborders, as knowledge increases, 

 more and more structurally transitional forms between these and the 

 basal Percoidei become known. Thus, to a greater or lesser extent, 



