44 THE V0YAC4E OF H.M.S. CHALLENGER. 



limb of the vomer (y.) is seen, and the broad palatal part lies on the palatal skin. On 

 each side at this part there is a large tube, these are the inner nasal passages (i.n.), and 

 they are walled in by the semi-tubular palatines (jxi.), which are kept apart above and 

 below by the vomerine bars. On each side of the palatines the maxillaries {mx.) are seen, 

 each with a considerable palatine plate undergirding the palatine bones. 



Above, the. narrow fore end of the frontals (/.) are notched to receive the sharp inner 

 edge of the naso-jDrefrontals {p-f:n.) in their orbital portion. This section is behind the 

 ascending, and through the jugal, part of the maxillaries. 



Eighth Section. — The next section (PL XIII. fig. l) is through the back of the eyeball 

 (e.) and the mass of the huge lachrymal gland (l-g.) ; it is behind the posterior nasal 

 openings, and through the narrow fore part of the hemispheres (C Id). The orbito- 

 sphenoids (o.s.) here form a trough for the brain, and reach up to the under surface of 

 the frontals (/.), which thicken near their edge, and form the orbital eave. 



The septum of the orbits now becomes the presphenoid (j>.s.), and is scarcely lower 

 than in the last section. Below this wall the thin end of the upper limb of the vomer 

 (y.) is seen, and on each side of this the broad post-nasal part of the palatine {pa.), 

 Hanked by the terminal part of the maxillary palatine plate {mx.). 



Overlapping the frontals are the large post-orbitals {pt.o.), and stuck into their lower 

 edge the large jugals [j.), which are cut through behind the jugal process of the maxil- 

 laries. The floor of the mouth is cut through, showing the tongue {tg.), the fore part of 

 the larynx {Ix.), the top of the basi-hyal (h.hy.), and on each side the dentary (d), 

 embracing Meckel's cartilage (m^.), which has no " splenial" bone on its inner side. 



Ninth Section. — Here (PI. XIII. fig. 2) the widest part of the hemispheres (C 1«) 

 are seen, and the optic nerves (fig. 2) in the common optic passage. The back of the 

 eyeball and the lachrymal gland {e.,l.g.) are still in view, and we have still a large 

 orbito- sphenoid (o.s.). The vertical cartilage is the presphenoid (^.s.) just where it joins 

 the fore end of the basisphenoid. Under it the broad pterygoids (j^g-) are seen cut 

 across at their front part. Outside, the post-orbitals {pt.o.) are fixed into the frontals 

 (/), and are overlapped by the jugals {j.). 



Tenth Section. — This (fig. 3) is between the orbital and temporal regions ; the hinder 

 part of the hemispheres and the fore part of the mid-brain, passing into the fore-brain below 

 (C la, C 2, C 1), are cut across. Here the infundibulum is seen to jjass into the pituitary 

 body {inf.,py.), and this rests upon the " sella turcica " or hollow of the basisphenoid 

 (6.S.). This cup is flanked by the flat, horizontal pterygoids {pg.), which ascend somewhat 

 at this part. The roof and walls here are both made by the parietals {p.), which are 

 concave as they descend to rest their inner edge on the pterygoids and their outer edge 

 on the semi-osseous epipterygoids, whose shaft is cut across. The post-orbitals and 

 jugals {pt.o.,j.) are still in view. The mandible is cut through near the hinge, and the 

 Meckelian rod is here invested by the surangular, angular, and articular {mk.,s.ag.,ag.,ar.); 



