XXIV 



INTRODUCTION. 



have the culmen compressed and elevated into a low crest ; others have merely a median ridge 

 along the maxilla. It contains the smallest species of the family ; and they are those which, 

 according to the views of Dr. Murie, incline towards the Uptjpidjs. 



GEOGRAPHICAL DISTRIBUTION. 



The members of the family Bucerotida3 are found in but three of the zoogeographical 

 divisions of the globe, viz. the Ethiopian, Oriental, and Australian regions. Of these the last 

 possesses but few representatives, confined to its Austro-Malayan division ; for the Bucerotidse 

 are preeminently an Arctogean family, and have but few offshoots, and these are chiefly found 

 among the Notogean islands lying nearest to those composing the Indo-Malayan division of 

 the Oriental Region. 



Commencing with that part of the earth's surface in which these birds are found that 

 lies furthest to the westward, we enter Africa, in the Ethiopian Region, and observe that the 

 members of the family are natives of all the countries lying south of the Great Desert of the 

 Sahara, from the west to the eastern coasts and down to the Cape colony. Many species have 

 great ranges, some reaching quite across the continent, as they are met with on both coasts ; 

 while others of less extended dispersion still overrun several districts in which other very 

 distinct species have their habitat. This, indeed, is the case with members of the family in 

 all the different zoogeographical divisions in which they are found; and it thus becomes 

 extremely difficult, if not indeed well nigh impossible, to accurately designate the proper distri- 

 bution of many of the species. In Africa, the countries lying on the west coast contain the 

 largest number of the species found in the Ethiopian Region, viz. twenty out of twenty-seven, 

 several of which, however, extend their range quite across the continent. Of the remaining 

 seven, four only (so far as our knowledge of them enables us to decide) are confined to the 

 countries on the east coast, two have their range unknown or, at least, undetermined, and one 

 is generally distributed all over the continent. Beginning in the north-west, in Senegambia, at 

 the southern margin of the Sahara, we find that this district contains four species — viz. C. elata, 

 A. alboceistattjs, L. NASUTUS, and T. semieasciattjs. The first two and the last extend their 

 range to the Gaboon ; but how far into the interior, is unknown. The L. nasutus is a common 

 African species with a very extensive distribution, being met with in various portions of the 

 continent, such as Abyssinia on the east coast, and Sennaar, as well as the region of the Limpopo 

 river to Damaraland, on the south. It would appear to be an inhabitant of nearly all Africa 

 south of the desert. Proceeding southward along the west shore, we find in Eantee, Ashantee, 

 and the Gold Coast, seven well-marked species not before mentioned — viz. T. haetlatjbi, 



A. LEUCOLOPHUS, B. CYLINDEICTJS, S. ATEATUS, B. ALBOTIBIALIS, T. CAMUEUS, and P. PISTTJLATOE. 



Of these T. haetlaubi is only known from the Gold Coast. A. leucolophtjs seems to be 





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