THE PINEAL SYSTEM OF VERTEBRATES 183 



its development are simple are apt to become much folded by the ingrowth 

 of vascular processes of the surrounding mesoderm, so that in the fully 

 developed state the paraphysis has the appearance of a complicated 

 glandular structure and on account of its resemblance to the choroid 

 plexuses of the ventricles was termed by Sorensen the " plexus chorioi- 

 deus superior." In some cases, e.g. in Sphenodon, it grows backwards 



sob c 



rsh e 

 'A — /\ no 



pop 



S Op 



Fig. 132. — Dorsal View of Osteolepis macrolepidotus, one of the most 

 Ancient Types of Fossil Fish found in the Upper Silurian and Devonian 

 Strata, showing a Parietal Foramen in the Frontal Bone and between 

 Large Orbital Cavities. (After E. S. Goodrich.) 



e. : 

 Jr.. 

 io.c 

 it. : 



;'• •• 



/. : 

 m.c 

 mx. 

 n. : 

 na. 

 op. 

 Pf. 



ethmoid, included in rostral-shield, 

 frontals fused and enclosing pineal foramen. 

 : infraorbital canal, 

 intertemporal, 

 jugal. 

 lacrimal. 



: main trunk-canal. 

 : maxillary, 

 nostril. 



• nasal included in rostral-shield, 

 opercular, 

 pineal foramen. 

 p. op. : pre-opercular. 

 p. op. c. : preopercular canal. 

 pt.f. : post frontal. 

 pt. o. : post-orbital, 

 r. sh. : rostral-shield. 

 so. : supra-orbital. 

 5. ob. c. : supraorbital canal. 

 5. op. : subopercular. 

 sp. oc. : dermal supra-occipital. 

 sq. : squamosal. 

 st. : supra-temporal or pterotic. 



postorbital and supra temporal canal, 

 tabular. 

 c. : transverse occipital canal. 



stc. . 

 tb. : 

 t. oc 



