BuRKHARDT, Ncrvous SystoH of Protopteriis Annectens. 91 



it I suggest the name, lobus post-ollactorius [post-rhinal lobe 

 of Herrick Ed.] The lobe is found in the Amphibian brain, 

 but in a much reduced condition and correspond to what His 

 describes as the lobus olfactorius posterior in the human embryo, 

 forming the substantia perforata in the adult brain. The arach- 

 noid is developed only in certain regions, in the region where 

 the "adergeflecht " [plexus choroideus] is united to the bony 

 skull, again near the epiphysis. Over the fourth ventricle a 

 saccus endolymphaticus is found, which spreads itself widely 

 over the roof, and in it otoliths have been found. This sac is 

 not in comm,unication with the central cavity of the spinal cord.' 

 Taken in general, we may regard the brain of Protopterus 

 as a link between the amphibian and selachian brain, especially 

 when the fore- and mid-brain are considered. In a monograph 

 on the cen'ral nervous system of Protopterus annectens, which is 

 now in preparation, the observations here recorded will be more 

 carefully and more fully detailed. 



PLATE XIII. 



Fig. I. Median longitudinal section of the brain of Protopterus 

 annectens. Enlarged five diameters.® 



Fig. 2. Ventral view of the same. x2. 



Fig. J. View from the right side. X4. 



Fig. 4. Dorsal view of same. X4. 



i — X, cranial nerves, 7', /, <•/, ventral, lateral and dorsal roots respect- 

 ively; Com. ant. prrecommissura ; Con. conarium ; Di. diencephalon ; 

 Ep. epencephalon ; Hvp. hypophysis ; L. inf. lobi inferiores ; Lob. hyp. 

 lobi hippocampi ; Loh. pol. lobus postolfactorius [postrhinalis]; M. sp. 

 medulla spinalis ; T^fo. mesencephalon ; Met. metencephalon ; C//. optic 

 nerve ; Pros, prosencephalon ; PI. vent. IV. metaplexus ; Tr. ol. tractus 

 olfactorius; Tub. oi. tuberculum olfactorium; Z. epiphysis. 



•'During reproduction tliis i)late lias l)een soniewliat reduced. 



