420 THE AMERICAN NATURALIST. [ VoL. XXXV. 
inferior aspect of the postorbital in Dinichthys. There are in 
Macropetalichthys no movable ginglymoid joints, neither dorsal 
nor ventral armor so far as known, and apparently no ossified lower 
jaw. In short, this genus and the accompanying Asterosteus are as 
far removed from Arthrodires as are the Ostracoderms, and should 
perhaps be included in the same subclass with the latter. Their 
canal systems and cranial plates can be no more homologized with 
those of Arthrodires than with Stegocephalians, and the most we 
can affirm is that their arrangement is bilaterally symmetrical, and in 
a few respects similar or paralleled. Dean’s text-figures 12 and 13 
are objectionable, therefore, in so far as they depict merely fanciful 
conditions ; and in Figs. 15 and 16 the overlap of the clavicular is 
shown, but the plate itself is omitted. 
Apart from this parenthetical discussion, as it were, of extraneous 
genera, the author’s generalizations respecting Arthrodires, his sub- 
division of them into several new families, and summary of their 
characters, reflect the advanced ideas of an investigator who has 
greatly enlightened us as to their structure and interrelationships. 
CRE 
Jurassic Fossils from Alaska.!— In this paper Dr. Pompeckj 
has given a revision of all the known Jurassic fossils of Alaska and 
has described a number of new forms. According to Dr. Pompeckj 
the Lias is represented at Kialagvik, or Wrangell Bay, on the Penin- 
sula of Alaska, as shown by the presence of Amaltheus whiteavest 
White, ZZ/a howelli White, ZL. kialagvikensis White. This fauna 
was described by Dr. C. A. White as of Upper Jurassic or Lower 
Cretaceous age. 
The Kelloway stage of the Middle Jurassic is represented at Kat 
maiskoj on the southeastern side of the Alaskan Peninsula, and on 
the northwestern side of the Kadiak Island. The former locality 
furnished the following fossils : 
Cadoceras wosnessenski Grewingk, C. grewinghki Pompeckj, C. cato- 
stoma Pompeckj, Belemnitella, sp. indet., Aucella, sp. indet., a 
mus, 55. indet. The locality on Kadiak Island yielded the following 
fossils: PAy/loceras subobtusiforme Pompeckj, Cadoceras conf. wosnes 
senski Grewingk, C. grewingki Pompeckj, C. Schmidti Pompeckj, C. 
petelini Pompeckj, C., sf. indet., C. stenoloboide Pompeckj. TE 
fossils show a wide distribution of the sea during the Kelloway stage 
1 Pompeckj, J. F. Jura-Fossilien Alaska, Verhandl. Kais. Russ. Mineralo: 
Gesell. St. Petersbourg, Ser. 2, Bd. xxxviii (1900), Nr. 1. 
