DISTRIBUTION OF THE GULLS AND TERNS. 399 



mucli as beyond the Neotropical district no other hooded gull is 

 known to exist in the southern hemisphere. The Neotropical re- 

 gion, which has been so well worked out by Messrs. Sclater and 

 Salvin, possesses three other indigenous species, two of which, L. 

 maculipennis, Licht., audi, glaucodes, Meyen, only differ in a slight 

 degree in the pattern of the wing-feathers. Their geographical dis- 

 tribution is, however, somewhat remarkable — the former ranging 

 from South Brazil down to South-eastern Patagonia, where it stops, 

 its place being taken from the Falkland Islands round to Chili by 

 L. glaucodes. At the first glance, both these species much resemble 

 our well-known L. ridibundus, L., of the Palsearctic region, and 

 they appear to be its southern representatives. Along the Andean 

 range from Chili to Ecuador is found a much larger and handsome 

 species, L. aerranus, Tschudi, which breeds on the shores and islands 

 of the Lake Titicaca and other lakes at a considerable elevation, only 

 visiting the Pacific coast during the bad weather in the mountains. 

 Any other Jiooded species found in this region are merely winter 

 visitants from the north, and the most abundant of these is L.franTc- 

 lini, a Subarctic species which breeds in the Fur countries, and 

 ranges through North America west of the Mississippi, Mexico, and 

 down the Pacific coast to Chili. Of the remaining two American 

 species, L. atricilla, L., which has black primaries, inhabits the 

 temperate and intertropical regions of the Atlantic and Pacific 

 coasts ; and L. philadelphicd (Ord), {L. honapartii, Rich.), ranges 

 right across Subarctic America, descending both coasts, an im- 

 mature straggler occasionally finding its way to the British Isles. 

 In the Palsearctic region, L, ridibundus, L.,is found throughout 

 its whole extent, descending in winter as far as 15° N. lat. On 

 the Indian coast it then impinges upon the domain of its stouter 

 relative L. brunneicepJialus, Jerd., a species which has its summer 

 home in the lakes of the lofty tablelands of Tibet and Mongolia. 

 Straggling along the Atlantic coast, but in the main confined to 

 the Mediterranean and Black seas, is L. melanocephalus, Natt. ; 

 whilst that giant amongst the black-headed gulls, L. iclithyaeUis, 

 ranges from the Mediterranean to the Bay of Bengal. Along 

 the coasts and over the inland waters of China and Mongolia is 

 found a very peculiar gull, L. satmdersi, with which my lamented 

 friend the late Mr. E. Swinhoe did me the honour of associating my 

 name : it has remarkably slender feet and tarsi, resembling those 

 of a marsh-tern, with a very stout and powerful bill. The smallest 

 of all the gulls, L. minutus, Pall, ranges over the whole Palse- 



