410 BULLETIN 15 3, UNITED STATES NATIONAL MUSEUM 



against 225 millimeters, while epirhinus agrees in size with nasutus 

 but differs from both in having the casque well developed and pro- 

 duced anteriorly, ending with a rather pointed tip. This is true of 

 the males only. According to Reichenow,^'' the females can be dis- 

 tinguished by the white terminal edges of the remiges which are found 

 in nasutus and not in epirhinus. Lonnberg *" writes that this last 

 character is not constant and has therefore no taxonomic value. 

 Nevertheless, if due allowance be made for wear, this character does 

 hold fairly well, but a very worn female Tutsutus can not readily be 

 told from a similarly abraded epirhinus. In fresh plumage epir- 

 hinus has the remiges tipped with light grayish or brownish white, 

 but the tips are not as wide or as pure white as in nasutus. The dif- 

 ference is one of degree rather than a definite absence or presence of 

 this character. 



In central Kenya Colony (between the equator and the vicinity of 

 Nairobi) overlapping and intergrading take place, rendering it dif- 

 ficult to draw the geographical limits of the two forms. Thus, Van 

 Someren *^ records typical nasutus from Fort Hall, while Lonnberg *" 

 lists epirhinus from Nairobi, It appears that the latter race reaches 

 its northern limit in the Kikuyu and Ukamba country, and that 

 nasutus, like many Somaliland forms, occurs in the coastal strip 

 almost to Mombasa, where it is replaced by epirhi7ius. 



The gray hornbill inhabits a rather wider range of ecological, 

 habitats than most of the members of its genus. It is found in both 

 open thornbush country, savannas, and wooded areas, but not in 

 dense forest. 



The material examined in the present study (37 specimens) illus- 

 trates the plumages and molts of this bird fairly well, 'and as these 

 are not well known, they are given here. 



Two young birds taken from the same nest on May 15 at Gato 

 River, near Gardula, are about half grown and have the remiges 

 and rectrices well enough along in development to shoAv the juvenal 

 plumage. The only difference between it and the adult feathering 

 is, curiously enough, a slightly paler gray on the sides and flanks 

 in the former. The white tips of the rectrices (except the median 

 ones, which lack the tips) have a small, median, terminal, dark 

 gray spot in them which is not present in any of the adult's ex- 

 amined, and may be characteristic of the first plumage. However, 

 its apparent absence in adults may possibly be due to wear. 



The juvenal plumage is not replaced by an early postjuvenal 

 molt, but is worn for about a year. This statement is based wholly 



*«Vog. Afr., vol. 2, p. 259. 



^'Kungl. Sv. Vet. Akad. Ilandlgr., 1911, p. 72. 



«Nov. Zool., vol. 19, 1922, p. 76. 



