1897.] SKELETON OF PELODYTES PUNCTATUS. 591 



usually to be found in regions where such absorption is proceeding, 

 but at the same time the general proportions oi" the basal plate 

 suggest that it is quite possible that this process does take place. 

 The newly added cartilages {pa., fig. 7) at the inner edges of the 

 anterior ends of the hyoid arch are now directed towards one 

 another, having lost their forward slope; and the line of junction 

 between them and the original hyoidean cartilage is still apparent. 

 The greater part of the ceratohyal has become diminished in 

 thickness so as now to have the form of a bent rod of approxi- 

 mately uniform diameter. About the level of the bottom of the 

 hyoglossal sinus the ceratohyals exhibit the first indications of the 

 absorption which later results in the dismemberment of the arch 

 {h, fig. 7). A new notch or sinus {fl., fig. 7) has developed at the 

 side of the basal plate, mainly by the absorption of the cartilage in 

 that position. But the sinus is rendered more complete by the 

 simultaneous outgrowth of a process ( pal., fig. 7) which is to be 

 identified with the antero- lateral or alary process of the hyoid 

 apparatus of the Frog {pal., fig. 11). In consequence also of this 

 outgrowth of cartilage the middle of the three lateral sinuses, that 

 between the antero-lateral and the postero-laterul processes, is 

 beginning to make its appearance. 



Stage 8. Distance from snout to cloaca, 17 mm, Lenyth of liincl 

 limb, extended, 25 mm. Length of fore limb, extended, 9 mm. 

 (Plate XXXV. tig. 8.)^ 



The basal plate or body of the hyoid is now small in proportion 

 to the size of the outstanding processes. The postero-lateral process 

 •( P2}1; fig. 8) is longer thau before but not appreciably thicker ; 

 the sinus of which it forms the posterior boundary is much deeper 

 than in the last stage. The antero-lateral process {pal.) baa 

 enlarged and is already somewhat dilated at its extremity. The 

 first of the three lateral sinuses {Jl.) has now the form of an 

 ellipse, incomplete externally. One of the most noteworthy 

 features about this stage is the separation of the distal part of the 

 hyoidean cornu. The absorption of cartilage leading to such 

 separation occurs antero- externally to the last-mentioned sinus, 

 and the pointed form of the cartilage in this region shows that the 

 dismemberment has only recently occurred. Now that the outlines 

 of the constituents of the body of the hyoid have completely 

 disappeared, it is very difiicult to define the limits of that part of 

 the ceratohyal which is not detached, but I should judge that a 

 line drawn through the bottom of the hyoglossal sinus and through 

 the middle of the lateral sinus marked fl. would indicate the 

 proximal limit of the anterior or hyoidean cornu. The recently 

 added anterior processes (jjft.) are no.v indistinguishably fused 

 with the cartilage of the ceratohyal and are directed backvvardly as 

 well as inwardly. It is curious to note how these processes first 



1 The above spedmen, the hyoid of which is shown in fig. 8, happens to b« 

 slightly smaller than tliat repi'e»eul;ing Stage 7, but otherwise the two are 

 pert'ecily indistinguishable oxterually. 



39* 



