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TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



recognized." Hubbs, on the other hand (1919, p. 67), says that "The Microcyprini 

 (Poeciliidae and Amblyopsidae) were long confused with the Haplomi, but have recently 

 been shown to have a more advanced organization." He then cited the characters of the 



hyom 



AnabI 



Anableps tetrophthalmus 



CDS dovll 



Fig. 98. Anableps tetrophthalmus. 



branchiostegals, as noted above. Thus it appears probable that the Microcyprini represent 

 a specialized offshoot of the Iniomi-Haplomi group, which have evolved in the direction 

 of their cousins the true acanthopts. 



This conclusion appears to be in harmony with the evidence from a comparative study 

 of the otoliths by Frost (1926f, p. 474), whose figures show that the sagittae of the Micro- 

 cyprini in general vary around a "Microcyprinid" type which is notably different from the 

 central perciform type (Frost, 1926c, Pi. XXI, Figs. 6-31; 1927^, PI. V). Moreover, in the 

 Microcyprini the asteriscus, the second ossicle, is well developed and about half the height 

 of the sagitta, its position is upright and its form usually of the characinid type. "The 

 lapillus is [normally] the smallest otolith, and is often microscopic; it has the form of a bean 

 in many species, and resembles those of the Characinidje and the primitive cyprinid 

 Baralius . . ." (Frost, 1926c, p. 474) while in the Perciformes the asteriscus and lapillus 

 remain diminutive and without special features (1927^, p. 298). Thus the Microcyprini 

 appear to be entitled to the ordinal rank conferred upon them by Tate Regan. 



The skull of Anableps tetrophthalmus (Fig. 98) of this order has enormous orbits, the 

 upper borders of which protrude high above the level of the cranial roof. The very small 

 mouth lies wholly in front of the orbits. The maxillae form large, relatively flat flanges 

 which are excluded from the gape by the delicate premaxillse. The mandible is minute. 

 In accordance with the forward position of the mouth the quadrate, preopercular and inter- 

 opercular are likewise produced far forward, .and form a sharp angle' with the antero- 

 posteriorly extended hyomandibular. The opercular lacks a spine. The cranial roof is 

 broad and flat, without crests. To judge from the characters of the orbits and mouth 

 parts Anableps tetrophthalmus ought to be able to swim at the surface and pick up small 

 prey, such as water insects. 



The sklill top of "Goodea atripinnis" (= Characodon luitpoldii) has been figured by 

 Tate Regan (1911^, PI. VIII). As a whole this skull (Brit. Mus. Nat. Hist., No. 10265) 

 strongly suggests the Fundulus type. The mandible is extremely small and transversely 

 flattened. 



