416 HARRIS HAWTHORNE WILDER ON 
converge at the posterior end. There is necessarily a slight depression between them, 
but anything asmarked as the depression described by Wiedersheim and likened to a 
“sella turcica,” I have failed to find. Probably this outline would be much more noticeable 
in_cross sections, which were studied extensively by this author, and in a young animal it 
is likely that it would be proportionally more marked. The parabasal normally comes into 
contact with ten bones, eight upon the dorsal surface and two upon the ventral. Dorsally 
there are found in order, the two frontals, and the two parietals, by their uncinate and 
orbito-sphenoid processes respectively ; the two pro-otics, and the two exoccipitals, the 
latter almost anchylosed with it mm old adults. Upon the ventral side are the two vomers. 
The palato-pterygoids and the opisthotics come very near the parabasal, but form no defi- 
nite area of contact. 
The upper jaw.— Under this term may be included all the dentigerous bones of the 
skull proper, as the teeth of all these oppose those upon the mandible. In this group 
both of the typical arches are represented, the maxillary and the palato-quadrate, or the 
“inner” and “ outer arches” of W. K. Parker, the former by the premaxillaries and the 
latter by the vomers and palato-pterygoids. Each of these arches bears a row of teeth, 
and, when the mouth is closed, the single row on the mandible is received between the two 
upper rows. The internal or palatine row is longer than the external or maxillary. 
1. THE MAXILLARY ARCH. This arch is represented in most Urodeles by both pre- 
maxillaries and maxillaries, the latter extensive and ending in long, backward projecting 
processes which, in the recent state, are attached by strong ligaments to the quadrates, 
thus making the arch a complete one. In Necturus it suffers much reduction and is 
represented by the premaxillaries alone. The maxillary fails completely, and no rudi- 
ment of it seems to be present at any developmental stage. Hyrtl describes a dried 
specimen with a small but tooth-bearing mawil- 
lary upon one side. Neither Huxley nor Wie- 
dersheim could find a trace of it, and in an 
examination of more than fifty skulls I have 
never seen it. The specimen described by 
Hyrtl must have been either an abnormal case 
Sea0Gd Suipuarsy 
or one of mistaken identity. 
a. Premavillary.— This bone consists of 
DORSAL MEMT RAL a slightly curved alveolar portion, to the inner 
Fig. 16. Two views of right premaxillary. x 3. end of which an ascending process is added at 
nearly aright angle. The alveolar portion is 
placed in an antero-lateral position, ventral to the large nasal capsule, which lies obliquely 
across it and forms the anterior part of the outer margin of the skull. The ascending 
