INTRODUCTION. 
XCIU 
Genus Eeismatura, Bonap. 
The members of this genus, although but few in number, are found in Europe, Asia, Africa, America and 
Austraha. 
555. Erismatura Austrahs . . . . . . . . . . . . Vol. VII. PI. 17. 
This species, the only one of the genus inhabiting Australia, is, I believe, strictly confined to the western parts 
of the country, as hitherto it has not been seen elsewhere. 
Genus Biziura, Leach. 
A genus of which only a single species is known to exist, and which is singularly different from every other 
member of the family. It is strictly Australian, and may be regarded as one of the anomalies of its fauna. 
556. Biziura lobata . . . . . . Vol. VII. Pi. 18. 
Family LARIDiE, Leach. 
Genus Larus, Linn. 
The members of this genus are distributed over the sea-shores of every part of the globe. Only one species 
inhabits Austraha, to which country it is confined, and where it represents the Lams marinus of Europe and 
America. 
557. Larus Pacificus , . Vol. VII. PI. 19. 
s 
Genus Xema, Leach. 
A genus of Gulls, the members of which are delicate in their structure, elegant in their appearance, and 
graceful in all their actions. Many species are found in Europe and America, and others inhabit Africa ; one 
species only has been characterized as Austrahan, but I beheve that another will be found in Torres' Straits very 
similar to, but much larger than, the X. Jamesonii of the southern parts of that continent. 
558. Xema Jamesonii ........... . . Vol. VII. PI. 20. 
Subfamily ? 
Genus Lestris, ///. 
The high latitudes of both the northern and southern hemispheres are frequented by parasitic Gulls. 
One species of this form has been found in the Australian seas, and another has been discovered within the 
Antarctic circle. 
559. Lestris Catarractes Vol. VII. PI. 21. 
Although I have figured and described this Australian bird as identical with the Skua Gull of Europe, it is 
likely that hereafter reasons may be found for separating them. 
In a letter just arrived from Mr, J. M'Gilhvray, dated on board H.M.S. Rattlesnake, Feb. 6, 1848, that 
gentleman says, " The Lestris Catarractes was noticed on various occasions in different parts of the South Indian 
Ocean ; while off the Cape of Good Hope a solitary individual and subsequently two in company were seen. I have 
observed it following and hovering over a bait towing astern, and once saw it chase a Cape Petrel and force it to 
alight on the water. This bird seldom remained with us for more than half an hour at a time, during which it 
made a few circular flights about the ship." 
2 A 
