Dr. R. H. Traquair—On the “ Dendrodont” Fishes. 491 
“ Dendrodonts ” do not belong to the Ganoidei, but to the Dipnoi, as he 
had been able to prove the autostylic condition of the skull—“ d.h. das 
mit dem Schidel unbeweglich verschmolzene Palatoquadratum und 
das verkiimmerte Hyomandibulare.” On reading the paper, however, 
and examining the two very pretty plates by which it is illustrated, 
_ one is rather disappointed as to the evidence which Dr. Rohon has 
adduced to prove his position. 
It is of course not always easy to identify every part of a fossil 
fish skull from drawings only, but there are a few points concerning 
the fossil figured by Dr. Rohon as the ‘‘skull” of Dendrodus biporcatus 
which are self-evident. 
This “skull” (pl. i. fig. 1) is not the entire skull, with several 
body-vertebrae fused with it, as Dr. Rohon seems to imagine, but 
only the anterior part or snout broken off near the interorbital 
region. His “pterygo-palatine” bones are the two elements of the 
duplex vomer, each of which, as in the Rhizodonts and Saurodipterines, 
bears one or more large tusks. The skull being broken off quite 
anterior to the brain-cavity, it will hardly be appropriate to designate 
anything here displayed as ‘‘quadrate” or “ hyomandibular,” the 
parts so lettered being in reality ante-orbital in position! What 
Dr. Rohon interprets as orbit (though indeed with a query) is a 
crevice apparently at the postero-external part of the premaxilla. 
Dr. Rohon seems to put great weight on the ‘“einheitlichen 
Hautknochen ” by which the “Schadeldecke” is represented. The 
fusion of the dermal plates of the snout with the premaxille into one 
piece is not, however, a very rare phenomenon in Devonian Crosso- 
pterygii, and is indeed well seen in a large skull of Glyptolepis 
paucidens in the Edinburgh Museum. 
In fig. 8 Dr. Rohon represents a broken-off snout which he refers 
to a new species of Cricodus (C. Wenjuckowi). Here the supposed 
“orbits” have a most suspicious resemblance to nasal openings. 
The orbits in many old fossil fishes are anterior enough, it is true, 
but not quite situated upon the very front of the snout itself. 
In fig. 10 Dr. Rohon has given a view of a dentigerous fragment 
from Thurso which he supposes to be a part of a skull of Dendrodus 
showing the cranial cavity. As the diameter of the supposed cranial 
cavity is not greater than that of the base of the large tooth attached 
to the specimen, this interpretation can hardly be correct. 
Nor can I admit that the dentigerous fragment depicted in his 
fic. 11 represents the entire mandible either of Dendrodus or any 
other fish. I think also that Dr. Rohon is hardly entitled to explain 
the discrepancies between this fragment and the mandibles, figured 
by Pander, Trautschold and Agassiz, on the supposition that they 
belonged to fishes which, though “allied to the Dendrodonts in the 
structure of their teeth, were tolerably far removed from them as 
regards the constitution of the lower jaw, and probably also of 
the skull.” 
At the end of the paper he gives an “attempt at a restoration ” 
of Dendrodus biporcatus, Owen. Here the body and fins are formed 
as in Gyroptychius, and, if the author considers Dendrodus to be a 
