SOME POINTS IN THE ANATOMY OF STEATORNIS. 181 
though not strong; it continues simple as it descends, being of the 
same breadth as the lateral neck-spaces. Just above the upper or 
scapular extremities of the furcula it ceases in the middle line, 
leaving a bare interclavicular space; but it develops a branch on 
either side, which expands over the chest to form the pectoral tracts. 
The pectoral tract of each side is double, the inner of its divisions 
being the continuation of the main tract, which descends, narrow and 
strong, close to the carina sterni in its upper part, but further sepa- 
rated below, leaving over the epigastric region of the abdomen a con- 
siderable median space, which lower down is again reduced by their 
convergence to the anus, just in front of which they terminate. 
Each outer pectoral branch of the inferior tract is weak and very 
diffused, covering the sides of the body, leaving a narrow space 
between it and the main stem, except at the points just in front of the 
scapular ends of the furcnla, from which they spring, and below the 
inferior margin of the sternum, where they again blend, and continue 
down side by side, after their contact, nearly to the anus, the outer 
branch being the weaker and less defined. 
There is a weak hypopteral tract continued from the outer margin 
of the external pectoral branch. The under wing-surface is feathered 
along the forearm in several rows. The margin of the patagium is 
~ thickly set with short strong plumes. The humeral tract is strong 
and separated by a narrow space from the well-covered upper wing- 
surface. ‘ 
There is no aftershaft to the feathers. 
There are ten primary remiges, and twelve secondary, of which 
the ten distal resemble each other, and the two at the elbow are 
reduced in size. The upper wing-coverts do not extend more than 
or quite so much as halfway down the secondary remiges. There 
are ten rectrices. 
The above described pterylosis clearly indicates that in the arrange- 
ment of its feathers Steatornis more closely resembles the Strigide 
than the Caprimulgide, though it differs considerably from both. It 
resembles the Strigide and differs from the Caprimulgide in having 
no aftershaft to the contour feathers, in not having the occipital tract 
divided up into narrow longitudinal rows, in having spaces on each 
side of the submaxillary tract, in haying the pectoral portion of the Page 530. 
inferior tract in two parts, of which the inner approaches the carina 
a sterni above and separates from it as it descends, in having the upper 
; wing-surface uniformly feathered, and in having a large infundibuli- 
form oil-gland. In none of the Caprimulgide does the inferior tract 
continue simple down the neck, whilst in Striz flammea as in Steatornis 
it does not bifurcate till in the region of the furcula. But Steatornis 
resembles the Caprimulgide and differs from the Strigide in having 
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