3n from eiiemiei 



zine of Natum 



TRANSACTIONS OF SECTION D. 



71 



numbers of other fruit-eatin<^ bata abound. Indeed it is difHcult to 

 one of tliese great bats, -whose flight appears so slow and laboured compiired 

 witli that of all other species of ( !liiroptera, traversing CO, much lesa 500, miles of 

 unbroken sea — for, even if carried out to sea by a storm, their wings would 

 fvidpntly collapse long before they had travelled half the distance; on the other 

 lianil it is quite out of one's power to understand their present distribution, except 

 on the old grounds of independent creation, without postulating a mucli closer 

 connection than Mr. Wallace appears disposed to admit between the island groups 

 in the Indian Ocean at a comparatively recent period. 



The above-noted fticts lead to the followmg deductions, namely, that in the 

 first place a chain of islands sutllciently close to allow of the passage, not only of 

 the representatives of the genera of insectivorous bats referred to, but also of tlie 

 large slow-flying frugivorons bats, must have existed between ^ladagascar an<l 

 Australia ; and, secondly, tliat at a later period a temporary connection of a similar 

 kintl lay between Madagascar and India. 



It may be said that such connection with India would also permit of the intni- 

 duction of insectivorous bats ; but it must be again remembered that volant insects, 

 on which such bats feed, are very scarce in oceanic islands, while tree fruit, which 

 forms the food of the frugivorons species, is usually al)undant. Bearing tliese 

 ;';.tt3 in mind, it is necessary to suppose that the islands, assumed to have formed 

 the higli-road for the insectivorous bats between Africa and Australia, must have 

 !;;en sufficiently large to support volant insects ; while, on the other hand, a chain 

 fi:' small coral islands, placi'd not too far apart, and provided only with a few 

 riuit-bearing trees, would have suftired for the passage of the frugivorons species ; 

 Ami it appears more than probable that it was by such a chain that the ancestors 

 of the iiying-foxes of India were introduced into that continent. 



A review of the abovi'-noted statements lends strong support to the theory of 

 a continent, or series of large, closely connected islands, extending' acro.-s the Indian 

 Orean at a comparativelv recent period from Madagascar to Australia, which, 

 oriq-inally advanced by ^Ir. P. L. Sclater. F.R.S., is still inaintained by many most 

 important distributional fiicts. 



1. On the Geographical Dlstrihvti'm of the Lari'lrv {Gulls and Terns), tvitk 

 special reference to Canadian Sjiecies. By Howard Saundeks, F.L.S. 



The author pointed out that, excepting in the case of the circumpolar and sub- 

 arctic species of Larida, the Atlantic forms a barrier between the Gulls of the 

 Paltearctic and Nearctic regions ; and almost so with the Tenis. This be instanced 

 by reference to some European species and their Canadian representatives. Owing 

 to the belt of warm water between tlie tropics in the Atlantic, hardly any GfuUs, 

 and but few Terns belonging to the northern hemisphere, cross the equator ; but in 

 the Pacific, where the expanse of warm water is narrowed by the approximation of 

 the cold Humboldt's current, which runs from the Antarctic regions to the equator, 

 on the one side, and by the Japanese cold current, reaching nearly to the equator, 

 <'n the other, several species of Gidls which breed in the far jiorth, Avinter in the 

 southern hemisphere. The Pacific coast of North and South America is inhabited 

 by various species of Gulls differing widely in coloration from those of the Old 

 World, with the exception of a single species found in Japanese and Chinese waters, 

 and which presented intermediate characteristics. The North Pacific was, more- 

 over, tlie home of Sterna alcutica, which partakes of the coloration of the typical 

 Terns and of those of the inter-tropical Sooty-Tern group. It was only in the 

 Pacific that the winter range of the circumpolar forked-tailed gull, ATrmrj sabinii, 

 extended to the south of the equator; overlapping the area between the (Jalapagos 

 Islands and the coast of Peru, the home, so far as is known, of the very rare A'. 

 furcnta, only three specimens of which are in collections. Nearly al! the large 

 (julLs without hoods are found in the North Pacific and Bering Sea ; and there also 

 that peculiar marine genus, liis-ffi (the Atlantic representative of which, Jt. tridarfi/la, 

 has no developed hind toe), shows an approach to the typical four-toed Gulls by 



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^ijLd. 



