CHIONIS MINOR. 113 



lodgQient of the nasal glands not seen in Gallince. In fact, the curious 

 frontal bosses found ou some cocks are one of the most obvious points of 

 resemblance, aside from the fact that the palates of both are schizogna- 

 tlious) but a fortuitous exostosis like this has, of course, no classifica- 

 tory significance. 



On the other hand, every important feature of the skull is identical 

 with the characters presented by the skull of the gulls. So perfect is 

 the resemblance that after careful comparison the principal discrepancy 

 between the two skulls that we are able to detect is the wider divergence 

 of the pterygoids from each other, and the consequently more posterior 

 position of the palato-pterygoid articulation in the skull of Chionis. 

 The most trifling details of the gull's skull are repeated in that of Chi- 

 onis. It is needless to enumerate them. There is, however, a character 

 of uncertain vahie in the front of the gull's orbit, where a strong trans- 

 verse plate of bone projects, bounding the orbit anteriorly ; no such 

 formation being found in Chionis, wading, or gallinaceous birds. As to 

 the angle of the mandible, it is found to be in Chionis essentially as in 

 the gulls, yet with a slight production posteriorly, much like that found 

 in some wading birds. In general, the slight differences observed be- 

 tween the details of the skulls of Chionis and gulls are differences of 

 degree only ; a less development of bony ridges and processes, a greater 

 relative breadth, and less forcible expression of differential details. The 

 difference in the form of the rostrum, which is likely to attract attention, 

 is of no significance whatever, since extraordinary differences in this 

 respect are found among the Laridce themselves {cf. Bhynchops, e. g). 



Nitzsch first, from consideration of the pterylosis alone, and Huxley 

 subsequently, with reference to the skeleton, have demonstrated a very 

 close, although not generally recognized, connection between the great 

 plover-snipe group and the gulls ; and in discussing the affinity of Chionis 

 to the gulls, we might be supposed to imply nearly or quite as intimate 

 relationship with the plovers. But in Chionis we miss precisely those 

 characters which are relied upon to distinguish the plovers from the 

 gulls, namely, an extensive naked space above the sufirago as regards 

 pterylosis, and the presence of distinct basi-pterygoid processes as 

 regards osteology. Furthermore, plovers do not possess the great 

 pits on top of the skull which are so couvspicuous in Laridce and in 

 C/tiom's, their rostrum is slender and elongate, their maxillo-palatiues 

 are never swollen or spongy (as in Chionis), and the angles of their 

 mandibles are produced into slender recurved processes. 

 8 K 



