30 



THE BONES AND JOINTS. 



tilag-e. This cartilag-e fills the space bounded by the nasals above, 

 the parasphenoid below, the so-called ala marjna of the prootic bone 

 behind, and the sphenethmoid in front ; and has in its posterior part 

 an aperture (r) throug-h which passes the nervm opticns, and below 

 this a smaller one (v") for the nervus abilucens. The extent of the 

 cartilage in the antero-posterior direction is g'reater in R. esculenta 

 than in R. iei)iporarui., or in other words the sphenethmoid stretches 

 further back in the latter than in the former. 



B. The Bones of the Face. 



Firr. i' 



The Suspensorium. 



7. The squamosal 



bones, ossa tympanica, 



Cuvier (Figs. JO, 14 t). 



Cuvier, oss. foss., V, 2. 

 390, PI. XXIV, Figs. I, 

 2 n. — Dugès, temporo- 

 mastoidien, n. lo. — 

 Meckel, Articular part 

 of temporal. — HaH- 

 mann and others, quad- 

 rate-bone. — Parker 

 and Eettany, I.e., squa- 

 mosal. 



The suspensorium, 

 which forms the arti- 

 culation between the 

 cranium and the lower 

 jaw, is T shaped, and 

 consists of cartilage 

 covered by bone. Of 

 the three arms of the 

 T the anterior has a 

 free pointed extremity 

 (Fig. 14 t^) at the 

 postero-lateral margin 

 of the temporo-orbital 

 fossa : it forms a true 



processus zjjgomailcus, and is bound to the upper jaw by ligaments. 



In R. temporaria it is Comparatively much shorter than in R. 



esculenta. The posterior upper arm [1'^) articulates with the prootic 



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

 twice natural size. Cartilage shown by stippling. 



