154 



SHUFELDT. 



[Vol. XVII. 



Fig. 5. — Syrniu7n lapponicum (Thunb.)- 

 Skull seen from in front ; mandible at- 

 tached ; two-thirds natural size. (Shu- 

 feldt after Collett.) 



ture the cranium in Syrnium uralense, but in it the mandibular 

 parts are more powerfully developed ; the parietal region is 

 more pyramidal in contour, and with comparatively smaller 

 orbits than in that species. The cranium sees its greatest 

 height opposite the posterior margins of the orbits. The 

 asymmetry is chiefly due to the somewhat distorted develop- 

 ment of the osseous crest of the 

 right OS squamosum. The beak 

 is laterally compressed, but is not 

 especially strong; the mandibular 

 portion has a greater length than 

 in any other inland species, and 

 does not quite enter twice (1.9) 

 into the total length of the cranium, 

 not taking into account its horny, 

 integumental theca. The median 

 furrow upon the superior aspect of 

 the cranium is quite well marked 

 its entire length, being especially 

 so in the frontal region, posterior 

 to the supraorbital processes. 



The orbit has a comparatively 

 less diameter than in 5. uralense, 

 inasmuch as os alisphenoides is 

 notably short and thick, which is 

 likewise the case with that part 

 of either frontal which forms the 

 margin of the orbit superiorly. 

 The supraorbital processes are 

 situated far back, so much so that their apices, upon either 

 side, reach to a point upon the orbital crest of the os alisphe- 

 noides. Further, either one of these processes is very broad, and 

 develops as a long frontal extension, which is connected by a 

 membrane with the tubercle of the orbital wing, superiorly, and 

 in this manner contributes towards the formation of the hinder 

 roof of the orbital cavity. 



The osseous crest of the alisphenoid {processus orbitalis 

 posterior) is on the right side somewhat asymmetrical, as is 



Fig. 6. — Syrnium lapponicuni (Thunb.). 

 Skull seen from behind ; mandible at- 

 tached; two-thirds natural size. (Shu- 

 feldt after Collett.") 



