EXPLANATION OF PLATE IX. 



FIGURES. 



1. Notovyctes typlilops. Sacrum and pelvis, side view (x 2). 



ac, acetabulum. 



il, ilium. 



m, metapophysis of the fourth, or last, lumbar vertebra. 



mm, ankylosed metapophyses. 



o, obturator foramen. 



s, spinous process of third lumbar vertebra. 



ss, spinous processes of first caudal vertebra. 



t, transverse process of first sacral vertebra. 



tr, ankylosed transverse processes of sacral vertebrce, 



tt, transverse process of last lumbar vertebra. 



2. Dorsal view of the sacrum and pelvis (x 2). 



az, anterior zygapophyses. 



mm, ankylosed metapophyses. 



a, ankylosed spinous processes. These, meeting the metapo- 

 physes on the right side, form a completely closed canal. 

 On the left side the two sets of fused elements do not 

 quite meet, so that the canal is left open. 

 The foramina are those of the dorsal division of the spinal nerves. 



3. Ventral view of the sacrum and pelvis (x 2). 



ac, acetabulum. 



c, transverse process of second lund^ar vertebra. 



il, ilium, 



is, ischium. 



pz, posterior zygapophyses. 



sp, symphysis pubis. 



4. Outline of posterior outlet of pelvis (x 2). 



mm, metapophysis. 

 s, sj)inous process. 

 sp, symphysis pubis. 



5. Urinary and generative organs ; (half diagrammatic) ; ventral aspect 

 (nat. size). 

 a, anus. 



ad, adrenal. 

 ag, anal gland. 

 h, bladder. 



ep, epididymis. 

 h, kidney. 



p), penis, the point of which emerges within the cloaca from a 

 preputial sheath formed out of the cloacal wall (vid. fig. 6). 

 r, rectu.m. 

 t, testis. 

 u, ureter. 

 ur, urethra. 

 vd, vas deferens. 



6. The cloaca has been laid open by a dorsal slit, and the figure shows the 

 point of- the penis within it, slightly withdrawn from the sheath 

 formed out of the cloacal wall, in which, ordinarily, it lies almost 

 completely retracted. 



