SKUAS. 75 



closely, and so does the anatomical structure too. Without going further into detail, 

 we only mention that, in contradistinction to the foregoing groups, the members of 

 the present one have the part of the frontals occupying the space between the depres- 

 sions for the nasal glands widened to a flat surface instead of being a sharp ridge. As 

 to the palatal characters, may be noticed the presence of basipterygoid processes. 

 The superfamily is equal to the former order, Longipennes, minus the Tubinares 5 

 which here constitute the superfamily Procellaroideae, a separation to be closer dis- 

 cussed under the latter. 



Two, three, or four families are recognized in this group, according to the value 

 assigned to distinguishing characters by the different authors, viz., two when skimmers 

 and terns, on the one hand, are placed against jaegers and gulls on the other; three 

 when the two latter are deemed sufficiently distinct to form separate families ; four 

 when the two former are also allowed family rank. Notwithstanding the common 

 usage, the present writer is unable to detect even a sub-family distinction between the 

 gulls and the terns, while he is willing to regard the skimmers as constituting such a 

 division. The jregers he will treat as a distinct family, however. 



This family, called the STERCORABIID^E, consists only of a few species about half 

 a dozen which exhibit a series of characters not shared by the rest of the members of 

 the superfamily, being in many respects a remarkable and highly interesting group 

 of birds. One of the most obvious features is the so-called ' cere,' covering the basal 

 part of the beak above the nostrils ; this cere is by some authors said to be soft, others 

 again say that it is only a hard thin lamella, while the fact seems to be that both are 

 correct, but that it is soft or hard according to the season. In my opinion this cere is 

 the homologue of the ' nasal cuirass ' of the puffins, and is shed in precisely the same 

 manner, as I have a specimen from Kamtschatka which seems to be in the process 

 of shedding, a discovery here announced for the first time. The pterylosis deviates 

 somewhat from that of the Laridae, the feather tracts being considerably broader, 

 and the arrangement of the inferior tract different. Of anatomical features we will 

 only mention that the Stercorariidae have only one notch on each side of the poste- 

 rior margin of the breast bone, while the Laridae have two, and that in the former the 

 caeca are very much longer. 



We distinguish two genera, the members of which disagree not only in external 

 appearance, but also in their habits. The first one consists of the great skuas (Mega- 

 lestris) strong, large, dusky brown-colored birds, with the bearing of a large gull. The 

 bill is strong, and the tail is nearly even. One species inhabits the North Atlantic 

 (M. skua) while two representative forms are found in the antarctic seas. Dr. J. H. 

 Kidder had the opportunity of observing the habits of one of the latter (M. antarcti- 

 cus) while connected with the U. S. Transit-of-Venus Expedition to Kerguelen Island ; 

 and as his interesting sketch of its habits illustrates the peculiarities of the genus, we 

 introduce an extract as follows : " It was at first taken for a hawk by all of us ; its 

 manner of flight, watchfulness of the ground over which it flew, and habit of perch- 

 ing on spots commanding a wide view, all siiggesting this impression. It was, indeed, 

 difficult to believe the evidence of my own senses when I found a web-footed bird 

 avoiding the water, and preying solely, so far as my observation extended, upon other 

 birds. When any of the party went out shooting, he was pretty sure to be followed 

 by one or two ' sea-hens,' as the sealers call them, and had often to be very prompt to 

 secure his game before it should be carried off in his very presence. November 21, 

 in order to settle the question whether they attack and kill their own game when it is 



