202 PEOF. W. K. PAEKER ON THE MOEPHOLOGY 



the stipratemporal tract is oblong, curved, ridgy, and scabrous ; curling over the tegmen 

 tympani, it imbeds itself into the very substance of the bony roof of the horizontal 

 canal (h.sc). 



From above (fig. 1, sq) this upper part looks like a distinct plate from the lower. The 

 side view (fig. 3) corrects this false impresssion. 



The parasphenoid (fig. 2, pa.s) is not less elegant than the other parts ; its narrower 

 fore part is concealed by the palato-vomerine ankyloses ; thence it slowly widens, is much 

 hidden by the long tooth-beds, and then becomes winged behind. 



The larger basitemporal projections are hooked ; then come lesser snags ; and behind, 

 near the foramen magnum, the bone is transverse and gently emarginate. 



This bone is gently convex along its dentigerous part, but more so beneath the 

 medulla oblongata, where the endo-cranium is still deficient. 



The mandible (figs. 3 & 4) is quite normal ; on the outside (fig. 3) is seen the den- 

 tary (d), nearly reaching to the angle, and the coronoid region of the articulare (ar) is 

 seen above it. The condyle is cylindroidal ; in front of it the still thick cartilage lies in 

 the trough of the articulare, which is not so long as in many kinds of Urodeles. The 

 splenial (sp) is a long, narrow, pointed splint, with but four teeth in old specimens ; the 

 teeth gradually become uniserial and are carried by the dentary. 



The hyobranchial series of arches (fig. 5) have undergone their share of metamorphosis 

 (compare PI. XIX. fig. 9 with PL XXL fig. 5) ; and although several parts have been 

 absorbed, they are still a large and elegant structure. The hyoid arch is now perfectly 

 divided into a long, flat, curved, ceratohyal (c.hy) ; and a small terete hypohyal {h.hy), 

 which is loosely connected with its own main bar, and is turned backward to arti- 

 culate with the fore end of the first basibranchial (b.br x ). The first branchial arch is 

 now composed of two pieces of equal length ; the lower piece (c.br 1 ) is dilated and emar- 

 ginate below, and is attached loosely to its own basal bar (b.br 1 ). The upper piece 

 (e.br ] ) is only dilated below, where it has received into itself the substance of the second 

 epibranchial ; both the ceratobranchials (c.br 1 , c.br 2 ) articulate with it ; thus only the 

 lower segment of the second branchial arch is present now. This second ccratobranchial 

 is a slender rod, gently sigmoid, and articulates with the end of the first basibranchial 

 and the end of the first epibranchial. 



The 1st basibranchial is broad and spatulatc in front, with a straight fore edge ; it then 

 narrows, and is elegantly enlarged behind for the facets of the 2nd ceratobranchial. The 

 main bar of the 2nd basibranchial (b.br 1 ) has been quite absorbed, but its dilated hind 

 part exists as a large bony " thyrohyal ; " it is in the form of an unbent bow, the two 

 horns of which are united by a thick oval mass, the remnant of the longitudinal bar. 



I am able, thanks to Prof. Mivart, to give an illustration of another adult of this 

 group of Caducibranchs. 



Species 8. — The Skull of the adult Desmognathus fuscus. 



This is another N. -American Newt of the same group as the last ; its skull differs only 

 in unimportant particulars, but some of these arc very instructive. This skull is alto- 



