54 



THE VOYAGE OF H.M.S. CHALLENGER. 



Plate. 

 III. 



IV. 



Fig. 



3. 



4. 

 4a. 

 5. 

 6. 



■7. 



9. 

 10. 



11. 



The same object ; lower view, ...... 



The same stage ; vertical section of head, with brain in situ, . 

 Part of same object, ........ 



The same, with brain removed, ...... 



Same stage ; post-oral arches, upper view, . . . . 



Same stage ; First Section of a series made through the head 



at this stage, in a vertically-transverse direction. 

 Second Section of the same series, ..... 



Fourth Stage. — Third Section. A transverse section through 



anterior third of orbital region, . . . . . 



Fourth Section.— This displays the post-clinoid region, and is 



sub-parallel with the hind part of basis cranii, because of 



the sudden bend of the head, .... 



Fifth Section. — This is through the pituitary region. 

 Sixth Section. — This shows the relation of the pituitary 



" acini" to the infundibulum and fore brain. 

 Seventh Section. — Pituitary region still lower down. 

 Fifth Stage. — Upper view of head, with cranial basin laid open 

 The same head ; lower view, showing basis cranii, . 

 Third of a series of transverse sections (begun in the last 



Plate) ; this is through the fore part of the nasal cavity. 

 Fourth Section of the same series, just catching the eyelids. 

 Fifth Section. — Through back of nasal cavity and fore part of 



eyeballs, ........ 



Sixth Section. — This section is through the olfactory lobes 



and first third of eyeballs, ..... 

 Seventh Section. — In this section the hemispheres shown are cut 



through, 

 Eighth Section. — Through the internal nares, 

 Ninth Section. — Through middle of eyeballs, . 

 Tenth Section.— Through wide part of hemispheres. 

 Eleventh Section. — Through wide part of hemispheres and 



thalamencephalon, ...... 



Twelfth Section. — Through optic nerves, . . 



Xo. of Times 

 Magnified. 



8 diam. 



16 



13f 

 13f 



27* 



27i 

 27i 



n 



7J- 



12 

 12 



12 



12 



12 

 12 

 12 

 12 



12 

 12 



