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PACIFIC SCIENCE, Vol. XX, October 1966 
Thus Chaetodon and Caranx, representing 
the two extreme types of supraoccipital just 
described, both have high crests, but structurally 
and functionally they are far apart. Further- 
more, the two extremes represent quite differ- 
ent modes of life in the fishes that bear them. 
Any combination of them seems unlikely. Nor 
does it appear that one could be developed from 
the other except by going all the way back 
through some intermediate form with a rela- 
tively small, unspecialized occipital crest. Yet 
among Patterson’s derivations, he has the sharp- 
crested carangids and menids arising from 
Aipichthys, which according to his illustration 
(1964: Fig. 83) seems to have a chaetodontid- 
type (roofed) occipital process. Similarly, 
Spheiiocephalus, which Patterson has as a pro- 
genitor of the Serranidae, appears (Patterson’s 
Fig. 78) to have the broad-roofed crest of 
Chaetodon , not the cutting edge found in the 
serranids (Katayama, 1959). If the preceding 
analysis of supraoccipital crest development is 
sound, both of these derivations of Patterson’s 
would seem most improbable. 
But to belabor Patterson’s individual deriva- 
tions is probably overshooting the mark, for at 
the present time I see no reason to look nearly 
as far back as the berycoids for a percoid pro- 
genitor. It seems to me, rather, that some one 
berycoid lineage could have evolved a fairly 
long way, i.e., could have developed most of 
the characters listed previously, before branch- 
ing into the various percoid lineages, or even 
before giving off such subpercoid groups as 
the Mugiliformes. In short, I am far more 
impressed by the differences between the bery- 
coids and the percoids, or among the berycoids 
themselves, than by those between the various 
percoids. 
THE ARRANGEMENT OF PERCOID FAMILIES 
The 50 or so families of fishes included in 
the superfamily Percoidae have been grouped 
in various ways. Data on feeding and on jaw 
structure to be presented below support an ar- 
rangement proposed by Regan in 1913. In that 
paper Regan merely took up the families in 
serial order. However, in his introductory state- 
ment (1913:113) he said: "In the following 
arrangement a few of the more aberrant fami- 
lies are placed last, and the remainder are 
grouped into those without (Serranidae to 
Coryphaenidae) and those with a scaly process 
in the axil of the pelvic fins.” The process in 
question is made up of one to several modified 
scales that form a pointed projection extending 
back between the lateral border of the pelvic 
spine and the body. Among acanthopteran fishes 
the process occurs in some but not all members 
of the Beryciformes and Mugiliformes, and in 
the Perciformes it occurs among the Percoidae, 
Pomacentroidae, and Labroidae (Table 1). In 
the Percoidae the axillary process can be pos- 
tulated as being an independently developed 
or as an inherited character. Since there is no 
indication that the axillary processes of the 
Beryciformes, Mugiliformes, and Perciformes 
are not homologous, it seems more satisfactory 
to postulate that the percoid process has been 
lost one to many times in the families in which 
it is lacking (Table 1), rather than that a 
structure found in the Beryciformes and Mugili- 
formes has been lost and then redeveloped in 
certain members of the Percoidae. Within per- 
coid families the axillary process, when present, 
is fairly constant; exceptions are the Centropo- 
midae (Weber and deBeaufort, 1929:393), 
Sciaenidae (Norman, 1957:219), and Chaeto- 
dontidae (Fraser-Brunner 1 946:466). Percoid 
families with and those without axillary scales 
are listed in Table 1. "Above” the Percoidae 
axillary processes are found, to the author’s 
knowledge, only among the perciform super- 
families Pomacentroidae and Labroidae. 
It would seem that those families without 
and those with an axillary process are character- 
ized by two rather different modes of feeding. 
Percoid families without an axillary scaly pro- 
cess generally engulf their food, so to speak. 
Either the fish simply runs down its prey, 
merely opening its mouth at the appropriate 
moment, or food organisms in close enough 
proximity are sucked into the mouth by sudden 
expansion of the oral and branchial cavities. In 
either event the main problem is to get the jaws 
open at the right time, and the chief function 
of the unspecialized teeth is merely to grasp 
the prey. By contrast, the perciform families 
with an axillary process tend to specialize in the 
direction of selecting their food items with their 
front teeth. They may pluck it out from its 
