274 THE FIFTH DAT. [CHAP. VIII. 



2. The appearance of the knee and elbow, and of 

 the cartilages which precede the bones of the digits and 

 limbs. 



3. The formation of the primitive cartilaginous 

 cranium, more especially of the investing mass and the 

 trabecule, and the appearance of rods of cartilage in 

 the visceral arches. 



4. The developments of the parts of the face : the 

 closing in of the nasal passages by the nasal processes. 



5. A large development of grey matter in the 

 spinal cord as the anterior and posterior comua; con- 

 siderable growth both of the anterior and posterior 

 white columns, and the commencement of the anterior 

 and posterior fissures. 



6. The appearance of the auricular septum, of a 

 septum in the bulbus arteriosus, and of the semilunar 

 valves. 



7. The estabUshment of the several tissues. 



