156 



SHUFELDT. 



[Vol. XVII. 



especially more lofty than upon the left side. Regarding the 

 cranium upon its anterior aspect, it will be seen that the promi- 

 nent orbital wing completely conceals from view the osseous 

 crest of the right squamosal, while upon the left side the ex- 

 ternal border comes into sight beyond the orbital wing. Upon 

 the whole, the asymmetry of the cranium in this species can 

 best be appreciated by viewing it from above ; while thus seen, 

 one can also more easily compare the powerfully anteriorly 



directed superior bor- 

 der of the osseous crest 

 of the right side with 

 its retreating border 

 upon the left. (See 



Fig- 7-) 



Supraoccipital {squa- 

 ma occipitis) lacks, as 

 in vS. uralense, a supra- 

 occipital foramen. 



The pterygoid bones 

 are more slender than 

 in S. ahico and S. 

 tiralense, and possess 

 smaller articular facets 

 for articulation with 

 the palatines. Com- 

 paratively speaking, 

 the palatine bones are especially slender ; the lateral processes 

 of the ethmoid are well developed, and have an unusually high 

 point of origin, being upon a level with the olfactory foramen, 

 or slightly below the superior border of the lachrymal bone, 

 upon either side ; they are widely spread out, and when the 

 skull is seen from below, nearly the whole of either one of 

 them can be seen beyond the external border of the palatine 

 of the same side. 



The vomer is, as in other species of this genus, nearly rudi- 

 mentary, as it is only represented posteriorly by a minute 

 osseous spicula, being otherwise unossified (in subadult indi- 

 viduals, perhaps entirely so). 



Fig. 7. — Cranium of Symiutit lapponicum seen from above, 

 and showing the degree of asymmetry of the squamosal 

 crests ; compare this with Fig. 4, given above. (Adapted 

 by the author from Collett.) 



