Cope. | 58 [May 20, 
Nematognathi. The Dorypteride present a number of peculiar features, 
approaching still more closely the Physoclysti in their thoracic ventral fins. 
We may now consider the relations of the Lepidoides and Sauroides to 
the known physostomous orders. 
The scapular arch being suspended to the cranium renders comparison 
with some recent orders with a free scapular arch, unnecessary. The 
simplicity of the anterior vertebrae leaves out of account the Nemutognathi 
and Plectospondyli, The only orders with which we can compare them 
are those represented by their old companions in the Poissons Fossiles, the 
Ginglymodi, the Halecomorphi and the Lsospondyli. 
Although the Sawuwroides included the genus Lepidosteus in Agassiz’s 
system, I cannot find that any of the fishes of the two families under con- 
sideration possess the peculiar vertebree of that genus, which in part char- 
acterizes the order Ginglymodi. Neither have any of them the segmented 
maxillary bone. The real alternative is between the last two of the above 
named orders. Now the principal skeletal character which distinguishes 
these two, is found in the pectoral fin. In the Halecomorphi there are 
numerous basilar radii attached to a cartilaginous mesopterygium, in the 
Tsospodyli there are but three or four such bones sessile on the scapular arch. 
After examining a number of specimens of species of both the Agassizian 
families named, I have been unable to discover any basilar bones what- 
ever, and have suspected that they were, in the complete skeleton, of car- 
tilaginous character, Professor Agassiz figures this region in his restora- 
tion of the ‘‘ Lepidoid’”’ genus Platysomus, and of the ‘‘Sauroid”’ genera 
Macrosemius and Caturus. In these, he represents the small number of 
basilar bones characteristic of the Zsospondyli, and placed in the close rela- 
tion to the scapular arch, which is seenin the same order. A consultation 
of the numerous figures given by Agassiz, Thiolliere, and others, has 
failed to discover a single instance exhibiting the peculiar basilar pectoral 
bones of Amia. This could scarcely be so uniformly the case did such 
bones exist, so that with Prof. Agassiz restorations coinciding, I can only 
for the present refer these fishes to the Jsospondyli. 
Their other special characters are so numerous, that they must be taken 
account of in deciding on their ordinal relations. If we, for the present, 
distinguish the two families as did Agassiz, we include in the Lepidoides 
the genera with teeth en brosse or in a single row, and sub-equal and ob- 
tuse ; and in the Sauroides the genera with teeth of unequal sizes, some 
being large and raptorial, the others minute. Of the Lepidoid genera, 
Agassiz states that the vertebree are osseous in Lepidotus, and says the 
skeleton of Amblypterus is osseous, without particularizing the vertebre. 
The posterior vertebre of Paleoniscus he states to be ossified, while 
in Platysomus, Tetragonolepis and Dapedius, the centra are not certainly 
osseous. In all of these genera the neural and hemal arches are distinctly 
articulated with the centra. Platysomus, Dapedius and Tetragonolepis, 
present the important character of a series of basilar interneural and inter- 
heemal bones, the interneurals commencing in Platysomus at the head. 
