No. I.] THE CRANIUM IN THE OWLS. 129 



lofty upon the right side, and situated far posterior to the orbit ; on the 

 left side greatly compressed, and comes in contact with the hinder margin 

 of the orbit above. Anteriorly, both osseous crests are produced as long, 

 forward-projecting processes ; that on the right side meets the posterior 

 border of the orbital crest of alisphenoid, and on the left is deflected, 

 so as to come in contact with the mandible. Medio-longitudinal furrow 

 exists upon superior aspect of cranium ; the skull's greatest depth being post- 

 orbital. Jugal linear. Vomer rudimentary. Supraoccipital foramen present. 



In the last group, which is created to contain Nyctala teng- 

 malmi, the cranium sees its greatest asymmetry, as this asym- 

 metry occurs in the left as well as in the right side. Tt is here 

 also that the os sqiianiosu^n with its osseous crest exhibits its 

 maximum amount of anomalous development. On the right 

 side the osseous crest is lofty, approaching the same plane 

 above in which lies the superior contour line of the head. On 

 the left side it is as decidedly drawn downwards, and with the 

 tongue-like process on the osseous crest likewise so markedly 

 inclined in the same direction that the apex of the latter is in 

 direct contact with the lower jaw — a condition which is per- 

 haps unique for this genus in the class Aves. 



I have already availed myself of the opportunity to point out 

 the cranial asymmetry in N. tengmabni in an article that has 

 since appeared in the Proceedings of the Zoological Society of 

 London for 1871, p. 739, entitled "On the Asymmetry of the 

 Skull in Strix tengmalmi " (it having been sent in June of the 

 same year); and also in Vid. Selsk. Fork. Chria., p. 68, 1872. 

 Auricular openings are broad and wide, and have a depth equal 

 to that of the head ; both these and the ear-flaps, which are not 

 very broad, are of the same dimensions upon either side, other- 

 wise they present no asymmetry other than that which pertains 

 to the cranium itself. Apart from the asymmetrical structures 

 seen in the latter, it is perhaps most like that part of the skel- 

 eton in Syrniiini ahico, and has, as in that species, a notably 

 wide interorbital septum, part of which is transparent, and a 

 uniform convexity of its posterior aspect. 



The three resident species occurring in south and middle 

 Europe, viz., Strix fla7nmea (Linn.), 1766, Athetie noctua 

 (Retz), 1800, and Scops giu (Scop), 1769, together with Asio 

 capensis (Smith), 1835, which occurs as a straggler in the 



