TIIK HONKS AXI .I01XTS. 



anterior end of the maxillary bone ; from the same spot a horn- 

 shaped cartilaginous process (ri\ n'") curves round backwards and 

 towards the middle line. This projection bounds the nasal cavity 



externally, sending off 

 a free process ("'"} 

 on the way, and ends 

 w T ith a double point on 

 the roof of the carti- 

 laginous nasal cavity 

 (n""}. On the floor of 

 the nasal capsule, on 

 either side, is a knob- 

 shaped cartilaginous 

 eminence, running 

 from behind, forwards 

 and outwards; this may 

 be regarded as an in- 

 dication of a turbinated 

 bone. From the an- 

 terior wall there passes 

 into each nasal cavity 

 an almost horizontal, 

 partly ossified plate 

 (<?.M.),ending posteriorly 

 in a free pointed bor- 

 der. These are the 

 cornets of Duges (/. c., 

 p. 12, PI. I, Figs, i, 

 5), who correctly re- 

 garded them as tur- 

 binated bones. Cuvier 

 described them as rudi- 

 mentary nasal bones'. 



The alar cartilages of the nose have still to be described. They 

 are (a.n.) shell-shaped cartilages, hollowed out on the inner sides and 



1 Cuvier (Ossem. fossil., V, 2. 388) says that these little bones are fixed outside 

 the nasal cavity, so that we may suppose that he confounded them with the 

 nasal cartilages found in this situation. Duges correctly indicates their position 

 to be inside of the nasal capsule. Meckel (Vergl. Anat. II, 504) also regards 

 them as nasal bones. Bruch (Wurzb. naturwiss. Zeitschrift, vol. II, 1861, p. 213) 

 could not find them in any frog-skull, doubtless because he did not look inside the nasal 

 capsules. 



Cartilaginous basis of the skull of Rana esculenta, from above, 

 twice natural size. Cartilage shown by stippling. 



a.n. Wings of nasal cartilage. 

 c.n. Concha nariiim. 

 e Sphenethmoid. 



Foramina of cranium. 



Nasal. 



Pronto-parietal. 

 t Premaxillary. 

 j Quadrato-jugal. 

 m Maxillary. 



n,xn Cartilaginous nasal skele- 

 ton. 

 n', n", n"' Processes of the 



cartilage, 

 o Exoccipital bones. 



p. Prootic. 



l>t Anterior arm of pterygoid. 



pt' Posterior arm of ptery- 



*' Cartilaginous cranium. 



sp Cartilage of suspensorium. 



sp' Cartilage under the gqna- 

 muaaL 



tp" Cartilage under the ptery- 

 goid. 



A , n ^ or ) arm of the 

 Middle 



P Post 



interior ^ 

 [iddle j- 

 'osterior ' 



squamosal. 



