Mr. A. D. Bartlett on the Affinities of Balseniceps. 137 



Directing my attention to the skin of Balteniceps, I was surprised 

 at finding on the lower part of the back, reaching from the end of 

 the scapulars to the base of the tail, two large, weU-defiued powder- 

 down patches. The drawing ( fig. 1) represents these two patches 

 in situ on the body of the bird stripped of its feathers. These 

 remarkable patches are dark-coloured on the inside of the skin ; and 

 on the outside the down is of extreme thickness, and the quantity 

 of white or grey powder very great. This powder, when examined 

 under the microscope, appears excessively oily, and will not mix with 

 water. It is greasy to the touch, and is evidently produced by the 

 growth of the down. It appears, in fact, to be the quill-shafts of the 

 down broken up ; or perhaps the down roots secrete this powder, 

 which is distributed over the entire plumage, rendering the feathers 

 impervious to water, in the same way that the oil-glands eflFect this in 

 other birds. In this bird, however, the oil-glands are extremely small, 

 not larger than the oil-glands of a Sparrow. 



With reference to these patches, it is my intention to point out 

 in the birds that I consider allied to BalcBiiiceps the existence of 

 these patches of down ; and I may remark that the attempt to 

 arrange animals by such means is not new, as, for instance, in the 

 case of the Ruminants, some of the genera are distinguished by 

 pecuhar patches of hair, which are said to be glandular, upon the 

 legs, &c. ; and, again, the Viverridce are distinguished by the existence 

 or otherwise of anal and other glands and pouches. 



I therefore proceed to point out the species more or less allied to 

 Balneniceps that exhibit these singular structures. In the New 

 World form {Cancromd) this structure appears to be most fully 



Fig. 2. 



Fig. 3. 



developed, this bird having four pairs of these powder- down patches, 

 as shown in fig. 2, which represents the upper, and fig. 3, which 



