96 TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



Some of the other reasons why I cannot accept many of Dr. Leighton Kesteven's 

 results are as follows: 



By comparing chiefly a few modernized or highly specialized representatives of existing 

 teleosts, reptiles, birds and mammals, Dr. Kesteven has persuaded himself that the so-called 

 premaxilla and maxilla of the teleost are not respectively homologous with those of the 

 higher vertebrates, including man. But he has not recognized that the premaxilla and 

 maxilla of the teleost can be traced back with only relatively small breaks in the phylogenetic 

 series to the premaxilla and maxilla of the palseoniscoid ganoids, such as Cheirolepis and its 

 allies, which are generally and rightly regarded by all authorities as being the oldest and 

 most primitive Devonian representatives of the entire actinopteran series. Now there 

 seems to be no reasonable ground for suspecting that the premaxilla and the maxilla of these 

 stem actinopterans are not respectively homologous with those of their contemporaries the 

 very primitive crossopterygians Osteolepis, Eusthenopteron, etc. Assuredly the entire com- 

 plex relations of the premaxillae and maxillae to the contiguous elements of the palate are 

 strikingly similar in the basic Actinopteri and Crossopterygii and in this case the phylo- 

 genetic relationships are too close to justify an appeal to "convergence." If the homologies 

 be admitted then the steps from the crossopterygians to the oldest amphibians, from these 

 to the most primitive reptiles, thence up through ascending grades of the mammal-like 

 reptiles to the lower mammals, Eocene primates, anthropoids and man, seem to be too 

 closely graded to warrant hesitation in accepting the usual identification of the premaxillse 

 and maxillae of teleosts as the upper outer jaw elements (Gregory, 1929). 



Similarly, I can find no merit in Dr. Leighton Kesteven's suggestion that what were 

 formerly labelled vomer (= prevomer) and palatine in the teleosts should now be called 

 premaxilla and maxilla, because the very same evolutionary series mentioned above (which 

 has been discovered by the cumulative researches of palaeontologists) also tends strongly to 

 confirm the view that the palatine and pterygoid of the teleosts were correctly identified by 

 the older authors. 



Similar considerations compel me to reject Dr. Kesteven's other identifications, e.g., 

 the teleost parasphenoid with the paired pterygoids of higher vertebrates, including man. 



Are the PREMAXiLLiE Compound Elements? 



In the course of his careful description of the cranial elements of the mail-cheeked 

 fishes. Dr. AUis (1909, p. 24) conies to the conclusion that the ascending processes of the 

 premaxillae of these and other teleosts are primarily a pair of independent bones which have 

 become fused with the premaxilla of lower teleosts. The latter, he thinks, have an articular 

 process of the premaxilla but not an ascending process. These fused elements he compares 

 with the median dermal ethmoid of Amia and with the paired "bone 2" of the ethmoid 

 region of Huxley's description of Esox, which are the same as the "proethmoid" of Starks' 

 description of that fish (1926fl, p. 202). 



After repeated consideration of Dr. Allis' discussion, I can only say that the evidence 

 cited by him seems to be largely irrelevant to the point in question for the following reasons: 

 first, not one of the teleosts cited by him shows any good evidence of the actual fusion of 

 paired superficial ethmoidal elements with the premaxillae, or even any evidence of the func- 

 tional association of the proethmoids with the premaxillas rather than with the ethmoid. 

 (The supposed case of Sphyrana cited by AUis is discussed above.) The conditions in 



