51�Թ�

Description.—Black; large alar speculum, axillaries, and under wing-coverts white; bill pale yellow; feet brown: total length 5·8 inches, wing 2·9, tail 2·5.

Grebes in general, though averse from taking wing, have much greater power of flight than would seem possible on examination of their alar organs, and are capable of prolonged aerial journeys.

Abbreviations for feather tracts in which downs were found: ca, capital; h, humeral; a, alar; d, d´, dorsal; cr, crural; v, ventral.

In this coral the calicle is divided into quadrants by four principal septa, the main septum, counter septum, and two alar septa.

Here the alar and basal laminae are both found, but the former is the more important; from it the optic thalami are derived, and more posteriorly the geniculate bodies.