REPORT ON THE GREEN TURTLE. -43 



Fourth Section. — This section (fig. 7) shows the finished nasal pouches, for the laminae 

 of cartilage are continuous, and below they curl upwards close to the broad base of the 

 steep and thin septum nasi {s.n.). The mucous membrane is folded inwards at the upper 

 third. Here we come across the palatine plates of the premaxillaries (p.px.), and the 

 maxillaries (mx.) are thick, steep, and sharp-edged. ' 



Fifth Section. — The eyelids are first reached in this section (fig. 8), for the large 

 orbital space lies somewhat over the nasal pouches ; these are complete tubes at this part, 

 for the lower edge, as it ascends into the inside of the pouch, sends inwards a process that 

 coalesces with the base of the septum nasi {n.f.,s.n.) ; there is an oval space between 

 these cartilages on each side. This structure is seen also in Falcons (Bird's' Skull, part 2, 

 Trans. Linn. Soc, ser. 2, Zool., vol. i., pi. xxv. figs. 2-6) ; those birds likewise have a very 

 Chelonian vomer, a short down-turned face, and a round nostril as in the Chelonian. This 

 section also is in front of the nasal roof-bone ; the palatal processes of the premaxillaries 

 {p-pX'-) are thinning out, and the dentary edge of the maxillaries {mx.) thickening. 



Sixth Section. — This slice (figs. 9, 9"), is taken from the widest part of the nasal 

 capsules, behind, close in front of the antorbital lamina (see fig. 1), where the wall is dented 

 inwards. This hollow is due to an ingrowth of the wall which becomes a free lamina 

 inside, and reaches almost half across the tube. In the higher " Sauropsida " this is coiled 

 upon itself twice, as a rule, and is the inferior turbinal ; here we have only a rudiment 

 {i.th.). The upturned nasal floor {n.f.) is now only articulated with the base of the 

 septum nasi {s.n.), and the tube of the last section is only a canal at this part. Immedi- 

 ately below the most bulging part of the nasal floor we encounter a cartilage which is 

 common in the " Ichthyopsida," and is a separate piece — for a time at least — in many; 

 this is the " ethmo-palatine " (figs. 9", 9\ cpa.) ; it becomes, by ossification, the true 

 palatine bone in bony fishes. 



Here it is so distant that in neither of its faces, front or behind (figs. 9", g', e.2'>a), could 

 I find any confluence with the nasal capsule ; but in Lacerta and Chamcsleo, where it is 

 much larger and pedate below, it is early confluent by its stem with this part of the nasal 

 floor. Its true origin is from the trabecula, but it is pushed aside very early in these 

 types by the intrusion of the nasal pouch. Here the prefronto-nasals {p.f.n., nasals and 

 " ecto-etlimoids " in one piece) are cut through ; they are very massive bones. Below, the 

 palatal plates of the premaxillaries have given way to the broad arched vomer {v.) ; this 

 is its antero-inferior part, and forms, as seen in section, the keystone of a very elegant 

 arch, whose sides are formed by the maxillaries {inx.). 



Seventh Section. — Here (PI. XII. fig. 10) the eyeballs (e.) are cut through, and the 

 fore part of the cranial cavity is exposed, with the proximal part of the olfactory nerves 

 (1). The floor of the skull is made by the narrow fore ends of the orbito-sphenoids (o.s.), 

 and the vertical wall is the perpendicular ethmoid {p.e.) ; for those alee run along in front 

 over the back of the true ethmoidal region. Below the thick base of this wall the upper 



