— 27 — 



origin". If this bone is of dermal and not of perichondrial origin, it would seem as if it must be a 

 supraethmoid instead of a mesetlimoid, and that it must represent the missing ascending processes 

 of the premaxillaries. 



In the Cyprinidae, I can not determine whether the ascending processes of Sagemehl's de- 

 scriptions are those processes or articuLar processes. In a specinien of Tinea that I have examined, 

 there is but one process on the premaxilUirv, and it is in contact, in the median line, with its fellow 

 of the opposite side, as an ascending process should be. It seems however highly probable that this 

 process is simply an articular process, or perhaps that process fused with an ascending process. The 

 ascending process would certainly be wanting if, as Sagemehl states, the mesethmoid in the Cyprinidae 

 has, as in the Characinidae, an overlying dermal component fused with it. There is in Tinea, as 

 Sagemehl describes for others of the Cyprinidae, a ligamentous band that connects the process of the 

 premaxillary with the top of the ethmoid bone, and associated with the ligaraent there is a small 

 median bone, the rostral of Sagemehl's descriptions; and the apparent homologue of this ligament, 

 in Scprpaena, is associated with the articular rather than with the ascending process of the pre- 

 maxillary. 



The ascending process of the premaxillary in Amphibia and higher vertebrates is called by 

 Gaupp the prenasal process of that bone. As this process in fishes quite certainly arises by the fusion 

 of the supraethmoid with the premaxillary, the term supraethmoid process would seem a better one, 

 if a change is to be made. And as the antorbital bones of Amia and Elops, and the septomaxillary of 

 amphibians certainly do not belong, in their origin or development, either to the orbital or maxillary 

 series, either infranasal or extranasal would seem to be the proper term; extranasal being the term 

 proposed by Gaupp for the bone in the Amphibia. 



The articular process of the premaxillary has never heretofore been specially described, so far 

 as I can find, excepting by myself in Scomber and by Brooks ('84) in Gadus aeglifinus. It is, however, 

 of very general, if not constant occurrence in the Acanthopterygii and Anacanthini. I find it in all 

 the mail-cheeked fishes that I have examined, and also in Zeus faber, Uranoscopus scaber, Mugil capito, 

 Sphyraena vulgaris, Gobius cruentatus, Trachurus trachurus and Lophius piscatorius, and more or 

 less completely fused with the ascending process in Labrus, Crenilabrus and Chrysophrys aurata. 

 It is also shown, in a more or less definite manner, by Cuvier and Valenciennes ('29) in their figures 

 of Perca, Sciaena and Otolithus; by Brühl ('91) in his figures of Rhombus and Labrax; by Agassiz 

 ('33/43) in his figures of Ophidium and Vomer; by Shufeldt ('85) in his figures of Micro pterus; by 

 Supino ('01/02) in his figures of Pomatomus, Hoplostethus, Ruvettus and Macrourus; by Traquair 

 ('65) in his figures of Hippoglossus; by Girard ('51) in his figures of Triglopsis; and in Gasterosteus, 

 judging from Swinnerton's ('02) figures, it is probably present in much the same condition that it is 

 in Scomber. In the Characinidae, and possibly also in the Cyprinidae, it is found, as I have just 

 above described. In the descriptions that I have of other teleosts I can not positively recognize it. 

 It would seem to be present in Argyropelecus (Supino '01/02), that fish certainly having an important 

 ascending process. In Clupea harengus I find, on the internal surface of the premaxillaries, a small 

 articular eminence that may perhaps be its homologue; but, to definitely determine this, a much more 

 careful study of the bones and ligaments is needed than I have been able to at present give them. 

 In Silurus glanis there is, on the dorsal surface of the premaxillary, at the lateral edge of the meseth- 

 moid, a small process against the lateral surface of which the maxillary abuts, if not articulates. This 

 process is shown in Jaquet's ('98) figure 39, and would seem to be an articular process. In Esox, a 



