686 MR. P. L. SCLATER ON LEPTOSOMA DISCOLOR. [Nov. 28, 
I believe, the auxiliary plume is always deficient*. The upper 
ptilosis also appears nearly similar to that assigned by Nitzsch to 
Coracias and Eurystomus. The spinal tract bifurcates between the 
shoulders, leaving a wide featherless space. The branches are then 
discontinuous for a short distance, but reappear in two gradually con- 
verging lines, which unite on the rump. But here a very abnormal 
Fig. 5. 
feature presents itself, which is found neither in the Coraciide nor 
in any other family of the Order Picariz. This is two large and 
highly developed powder-down patches (p, p), which are placed on 
the flanks, on each side of the rump. They are of an oval shape, and 
measure about 12 inch in length by an inch in breadth. The deve- 
lopment of these lubricating organs may perhaps account for the 
atrophy and almost total disappearance of the oil-gland, which can 
scarcely be recognized in the minute papilla (0, fig. 5), situated at 
the base of the two medial tail-featherst. 
* Cf. Nitzsch, Pterylographie, p. 129. 
+ This is, I believe, the first instance of powder-down patches having been 
noticed to occur in any species of the Order Picariz. Nitzsch (Pterylographie, 
p- 53) describes them as met with in the following genera :— 
ONATICIELNS <avccere.sscssseesccccentes Order. 
BlanWepevessacsts secre esensscconssces Accipitres. 
(OIE TS: 6S baceaaoodesna beer aban 
PURUATNUS as eens dcca deh aceteakp secs Passerinz. 
MUIIFUIIILS Wises teiaceecore veaeeeresece Gallinz. 
Ardea and its affines............00- | 
(CANCOME o5e00e scans ccvc-deeeseecsne Gralle. 
MENDY Gale icc swocceectseeetarcrares J 
Mr. Bartlett has determined their presence in Baleniceps (P. Z. 8.1861, p. 131) 
and Rhinochetus (ibid. 1862, p. 218). 
