16 



(/) Hemove carefully, under water,. the parieto-frontals, the right nasal, 

 the right premaxillse, maxillae, and squamosal. Examine and make 

 a sketch (2 nat. size), showing the exposed portion of the chondro- 

 cranium, the large anterior fontanelle, and the two small posterior 

 fontanelles, the exoccipitals, sphenethmoid, prootics, and quadrato- 

 jugals ; and, in addition, on the left side, the nasal, premaxillee, 

 maxillae, and squamosal. 



((/) Remove the skull from the vertebral column, and make a sketch 

 (2 nat. size) of the posterior aspect, showing the condyles (formed 

 by the exoccipitals) at each side of the foramen magnum, the 

 prootics, the columelles, and the upper ends of the anterior cornua 

 of the hyoid, the tympanic ring, and the suspensorium enclosed 

 between the squamosals and pterygoids. 

 2. The vertebral column. 



(a) Expose and make a drawing (2 nat. size) of the dorsal surface of the 

 vertebral column, showing the nine vertebrse and the long urostyle, 

 and indicate also the pelvic arch in connection with the large trans- 

 verse processes of the ninth vertebra (sacrum). 



(6) Observe the intervertebral foramina and the intervertebral discs, and 

 then examine the individual vertebrse, noting that the 2d to the 7th 

 resemble each other, while the 1st, 8th, and 9th are peculiar. 



(c) Make drawings (4 nat. size) of the 1st, 3d, 8th, and 9th vertebrte. 



(a) The 1 st or atlas vertebra. Indicate the forward projection of the 

 centrum, the narrow arch and rudimentary spine, the concave 

 facets for the occipital condyles, and the flattened articular 

 processes for the second vertebra, and note the absence of trans- 

 verse processes. 



(6) The 3d vertebra. Indicate the procoelous centrum, the neural 

 arch and its spine, the anterior and posterior articular processes 

 (zygapophyses), and the large transverse processes. 



(c) The 8th vertebra. Indicate in a section that the centrum is 



amphiccelous. 



(d) The 9th vertebra (sacrum). Indicate the single convex anterior 



facet for the 8th vertebra, the two convex posterior facets for 

 the urostyle, and the long expanded transverse processes which 

 support the iUa. 



(d) Make a sketch of the urostyle, showing the two facets in front, the 



cartilage projecting from the hollow posterior end, the dorsal ridge, 

 and the small aperture through which the 1 0th spinal nerve escapes 

 from the canal in the front of the ridge. 



