PLATE III. 



Fig. 25. Horizontal section through the head region showing the brain and sensory 

 nerves, and the relation of the anterior longitudinal nerve to the mar- 

 ginal nerve (n. pi'[>h.). The right-hand side of the section is a little 

 more dorsal than the left. X 52. 

 " 26-31. From a series of cross sections through the brain region. The sections 

 are taken at intervals of 00^. Figure 26 is the most anterior. X 52. 



• " 32-36. From a series of horizontal sections through the brain region, cut 

 from the dorsal side. The sections are consecutive, and 30 n in 

 thickness. X 52. 



