534 Mr. G. L. Bates on the Reversed [Ibis, 



Detailed Examination of the Reversed Coverts in 

 Various Birds. 



The Normal Type. — One type of major and median 

 under coverts is found in many large birds, belonging, for 

 the most part^ to orders that must be regarded as primitive 

 or little specialized. In this type the major under coverts 

 form a complete series, of large feathers, with a uniform 

 conforming overlap ; and the median series is complete on 

 the cubitus and extends on the proximal part, sometimes as 

 far as the middle of the manus, and consists of smaller 

 feathers, all having the contrary overlap. In the following 

 account, birds having this normal type of reversed under 

 coverts will be given first, and the others will follow in an 

 order intended to indicate roughly the amount of divergence 

 from the normal type. The arrangement is not intended to 

 be systematic — rather it is purposely not so, as the bearing 

 of this examination on questions of phylogenetic classifi- 

 cation must be left till the close. 



Pteronetta hartlaubi. Eight specimens examined, in- 

 cluding Nos. 5543, 5839 & 5840, the others not saved. 

 (Text-fig. 5.) 



The major under coverts all have the conforming overlap. 

 The series is complete, there being one covert for each 

 remex, and an extra one between the 4th and the 5th on the 

 cubitus. The 11th or most distal one on the manus is just 

 equal in length to its remex (the "remicle"), each being 

 30-33 mm. long ; this covert hides the remicle which is 

 very narrow. 



The median under coverts form a complete row on the 

 cubitus and extend to six feathers on the manus, besides 

 another extra one that is exactly at the carpal joint, as in the 

 accompanying diagram (text-fig. 6). These median coverts 

 thus do not exactly correspond in position to the major 

 coverts, but close upon one another and stand nearer 

 together, to a slight extent. 



The overlap of the median under coverts is contrary to 

 that of the remiges^ with the exception, at least iu some 



