Ill 
forms are found to exist ; the Australian fauna lias also a Gygis and 
an Onychoprion , neither of which inhabit the European seas, and 
four species of Anoiis , of which only one frequents the northern 
hemisphere. 
Genus Sylochelidon. 
560. Sylochelidon strenuus Vol. VII. PI. 22. 
A representative of the S. Caspius of Europe. 
Genus Thalasseus. 
The members of this genus, the type of which is the T. Cantiacus 
of the British Islands, are widely dispersed over most parts of the 
Old World, and three distinct species inhabit Australia. 
561. Thalasseus Pelecanoides Vol. VII. PI. 28. 
562. Thalasseus poliocercus, Gould .... Vol. VII. PI. 24. 
563. Thalasseus Torresii, Gould Vol. VII. PL 25. 
Since my account of this species was printed I have seen adult 
specimens from Southern India, which country is in all probability 
its true habitat. 
Genus Sterna. 
The members of this genus, as now restricted, enjoy so wide a 
range over the globe, that they may be said to be universally di- 
spersed : three species are found in Australia. 
564. Sterna melanorhyncha, Gould .... Vol. VII. PI. 26. 
565. Sterna gracilis, Gould Vol. VII. PI. 27. 
566. Sterna melanauchen, Temm Vol. VII. PI. 28. 
“ This beautiful bird,” says Mr. M‘Gillivray, “ is very local in 
its breeding-places, the only one known to me being one of the ‘ three 
sand-banks’ near Sir Charles Hardy’s Islands* The eggs are two in 
number, deposited in a slight hollow in the sand. I have seen this 
bird on another neighbouring sand-bank, also on Solitary Island, 
near Cape York, and in Endeavour Straits, but was unable to pro- 
cure a specimen from any of the three last-mentioned localities, on 
account of its excessive shyness. It is one of the most noisy of the 
Terns, and I generally saw it in small parties of half-a-dozen, or 
thereabouts. The fully-fledged young of the year differs from the 
adult in having the black on the head dark brown mottled with 
white, and the whole of the upper surface and wings variegated with 
dark brownish grey.” 
Genus Sternula. 
Europe and Australia are both tenanted by little Terns, the specific 
distinctness of which cannot be questioned, however much that of 
the large Terns (genus Sylochelidon ) may be : ought we not then 
to infer that some peculiar law prevails, and that if one be distinct 
the other is also ? However that may be, it is certain that birds re- 
