486 ALUS. [Vol. XI. 



3. The hypophysis and the saccus vasculosus in the adult of 

 Amia are both glandular structures. Both receive a consider- 

 able nervous supply direct from the base of the infundibulum, 

 and both communicate directly with the infundibular cavity. 



4. The olfactory nerve, contrary to Sagemehl's statement, 

 lies exposed to the orbit through a limited part of its course. 

 The opening through which it is so exposed lies at the extreme 

 front and upper end of the orbit, and gives passage to a vein 

 coming from the nasal pit. The olfactory canal in front of the 

 opening is therefore formed by the fusion of two canals, the 

 olfactory canal proper and what is probably the orbito-nasal 

 canal of selachians. The opening into the orbit can therefore 

 be called the orbito-nasal opening or fenestra. 



5. The "hitherto undescribed cranial nerve" of Pinkus in 

 Protopterus is found in Amia, part of its fibres arising with 

 the olfactorius and part of them having the intercranial course 

 described by Pinkus, though their definite origin from the 

 brain was not satisfactorily determined. In the nerve the 

 large cells described by Pinkus are found, scattered along the 

 nerve in old larvae, but in 12 mm. larvae gathered into a 

 knob-like protuberance on the under surface of the nervus 

 olfactorius at about the middle of its length. In general 

 histological appearance this collection of cells on the olfactorius 

 resembles at this age the ciliary ganglion found on the nervus 

 oculomotorius in much the same relation to that nerve. As 

 the ciliary ganglion is unquestionably in part at least a sympa- 

 thetic ganglion, the ganglion on the olfactorius is probably of 

 a similar character, and is possibly the sphenopalatinum of 

 higher vertebrates. 



6. The profundus ganglion is found both in larvae and 'in 

 the adult as a separate and distinct ganglion, connected with 

 the ciliary ganglion by a radix longa and with the brain by a 

 profundus root wholly separate and distinct from the root of 

 the trigeminus in larvae, but somewhat fused with that root in 

 the adult, 



7. There is in Amia no true ramus ophthalmicus profundus, 

 a nerve which, when found, lies ventral to the superior branch 

 of the oculomotorius and ventral to the nervus trochlearis. 



