PLATE XLI. 
NYCTOSAURUS GRACILIS. 
Fig. 1. Dorsal vertebre, ribs, and pelvis; about three-fifths natural size, 
r, ribs; dv, lumbar or false sacral; s, sacrum; zf, ischio-pubis; 04, obturator for- 
amen; 2/, ilium; 2%, prepubes. 
Fig. 2, Abdominal ribs. About three-fifths natural size. 
Fig. 3. Atlanto-axis, from the side. Twice natural size. 
Fig. 4. The same from behind, partly restored. 
Fig. 5. The same, from in front: a, atlantal neurapophysis; ac, axial cen- 
trum; az, atlantal intercentrum; azz, axial intercentrum; 4, ball of axis; 0, odontoid; 
pz, postzygapophysis. 
Fig.6. Hyoid bone. Three times natural size. 
Fig. 7. Extremity a of Fig. 6, more enlarged, from the side. 
