Studies on Avian Anatomy. — II. 
21 
fig. 24) is 26mm., the width 16mm.; in Aeronautes (G. bl., PI. V., fig. 
48) the length is 7mm., the width 4mm. The gall duct comes off 
from the anterior end of the gall bladder in Geococcyx and from 
the posterior end in both of the other birds. The gall ducts enter 
the ascending branch of the duodenum near the pancreatic and liver 
duets. 
The liver duct in Geococcyx (Liv. d., PI. I., fig. 13) comes from 
the central surface of the right liver lobe, posterior to the bridge 
connecting the two lobes, and near the gall bladder. In enters the 
ascending branch of the duodenal loop posterior to the gall duct 
and between the pancreatic ducts. In Bubo (Liv. d., PI. III., figs. 
24, 29) the liver duct comes from the right side of the bridge and 
enters the duodenum anterior to the gall duct. In Aeronautes (Liv. 
d., PI. V., fig. 48), about the middle of the right liver lobe comes 
off a liver duct which soon after leaving its surface receives a branch 
from the bridge connecting the two lobes. This duct then enters 
the ascending branch of the duodenal loop near the mid point of 
its dorsal surface behind the gall duct and anterior to the duct 
from the main branch of the pancreas. 
2. Female Urogenital Organs. 
The kidneys of Geococcyx (K., PI. I., fig. 28) are not fused. Each 
consists of three distinct lobes varying slightly in size, and a small 
right adrenal. In Bubo (K., PI. IV., fig. 32) the kidneys are not 
fused, and there is no distinct lobulation. In Aeronautes (K., PI. 
VI., fig. 58) the two separate kidneys possess each two lobes of 
almost equal size, and there are two larger adrenals. 
The ureters begin near the center of the kidney, between the 
anterior and middle lobes in Geococcyx; in Bubo near the anterior 
end of the kidney, and in Aeronautes near the posterior end be- 
tween the two lobes. All enter the cloaca on its dorsal surface, and 
median to the entrance of the oviducts. 
The left ovary and oviduct are well developed in Geococcyx (Ov., 
and L. Ovi., PI. I., fig. 9). The ovaries are small in Bubo (Ov., PI. 
IV., fig. 32) and Aeronautes (Ov., PI. VI., fig. 58). The anterior 
portion of the oviduct was broken and could not be studied in 
Bubo. The infundibulum was too collapsed to make out in Aero- 
nautes. In all the forms the right oviduct was represented by a 
blind sac. The bursa Fabricii (Bf., PI. IV., fig. 32) was present 
only in Bubo. 
3. Central Nervous System. 
The brain of all these birds is compact, not elongated, as in 
Phalenoptilus. Only a small portion is exposed. The greatest 
length of the cerebrum in Geococcyx (Cer., PI. I., figs. 1, 2, 3, 7) 
