132 SHUFELDT. [Vol. XVII. 



That Athene nocUm is doubtless especially closely related to 

 the genus Surnia can plainly be discerned from the structure 

 of the cranium alone. 



It appears that Kaup, in a paper {Trans. Zo'ol. Soc, Vol. IV) 

 to which I have not had access, has shown that AtJiene noctiia 

 presents an asymmetry (although slight) in the development of 

 these dermal structures.^ This asymmetry cannot, with cer- 

 tainty, be pointed out in a dry head that I possess, but in any 

 case must have been very slight. They are of medium size, or 

 relatively of about the same size as in Surnia fimerea, with the 

 flap absent. The cranium itself, which is symmetrical, agrees 

 in its main characters with the cranium in the last-named spe- 

 cies. The jugal bone is furnished with an elevated process ; 

 the osseous crest of the os squamosum resembles that struc- 

 ture as it occurs in Surnia funerea; but the greatest resem- 

 blance to this species is especially exhibited in the slender, 

 spine-like supraorbital process, which goes far towards making 

 clear the affinity these forms have with the diurnal birds of 

 prey (of the genus Astur) ; this also extends to the structure 

 of the cranium in these two species. 



In this particular the genus AtJiene comes nearer to the 

 genus Surnia than to Glaucidiuvi ;'^ on the other hand, it is 

 unlike both in possessing an evident median furrow. 



Scops giu has also relatively small or medium-sized auricular 



1 Kaup's figure appears in A History of North-American Birds (Baird, Brewer, 

 and Ridgway), vol. iii, p. 97. Boston, 1874. 



In this connection compare the pterylography of the so-called " Burrowing 

 Owls " of the American continent, reference being made to one of them in my 

 memoir entitled " Notes on the Anatomy of Speotyto cunicularia hypogoea " 

 {Journ. Morph., vol. iii, No. i, June, 1S89, pp. 11 5-125, PI. VII), also in a very 

 excellent paper by Mr. Hubert Lyman Clark, entitled " The Pterylography of cer- 

 tain American Goat-suckers and Owls," Proc. U. S. Nat. Mus., vol. xvii, 1894, 

 pp. 551-572. Many figures in text. The comparison of the feather-tracts of 

 Speotyto and Athene would be especially interesting. — R. W. S. 



2 The supraorbital processes are also spine-like and well developed in Speotyto, 

 as may be seen in my figures of the skeleton of that species {Bull. U. S. Geog. 

 and Geol. Surv. of the Terr. Dept. of the Interior, vol. vi. No. i, Washington, Feb- 

 ruary, 1881, Pis. I-III), but they are quite rudimentary in Micropallas whitneyi, 

 one of the smallest owls in the world, and belonging to a genus related to Glauci- 

 dium. Speotyto, Glaucidium, and Micropallas all possess the elevated process 

 upon the jugal. — R. W. S. 



