26 THE SALAMANDER 



plate. Both fenestrae are of course covered in the adult skull by the 

 parasphenoid bone. Practically the whole of the ear capsule except 

 the operculum ossifies in the mature adult, although the rim of 

 the fenestra vestibuli and the inner surfaces bounding the cavum 

 vestibuli tend to retain their cartilaginous nature. The combined 

 glossopharyngeus-vagus nerve passes through X^o, foramen post-otkuni 

 (fo.p-ot.) between the ear capsule and the occipital segment. 



The occipital ring remains almost entirely cartilaginous, and it is 

 only the deeper parts of the condyles which ossify and fuse with the ear 

 capsules. The composite ossification thus formed is best called the 

 occipito-petrosal (Stadtmialler). 



{d) The Palato-quadrate (c.p-q.). The suspensorium is attached 

 to the lateral aspect of the ear capsules by three processes, tripod- 

 like, so that a cavity with three exits is enclosed between the palato- 

 quadrate and the capsule. This cavity is the antrum petrosum laterale 

 (Druner), and through it pass the Art. and Vena petrosa lateralis and 

 the facial nerve. 



Of the three attaching processes the processus ascendens (pr.asc.) 

 is the smallest. It is continuous with the lateral skull wall and 

 separates the N. ophthalmicus profundus V from other two trige- 

 minus branches. It also separates the artery from the vein. Normally 

 the process remains unossified, but in old animals a certain amount 

 of perichondrial ossification may occur. The processus otkus (pr.ot.) 

 (proc. lateralis dorsalis, Druner) is the dorsal process and lies beneath 

 the squamosal. It is rather larger than the proc. ascendens, but, when 

 compared with the larval condition, it shows a tendency to lose its 

 connexion with the ear capsule through the ingrowth of connective 

 tissue (Stadtmuller, 1924). It remains cartilaginous. "XYit, processus 

 basalis (pr.ba.) (proc. lateralis ventralis, Druner) is by far the largest 

 of the three, and, as its name suggests, lies ventrally directly opposite 

 the proc. oticus. According to Stadtmuller it first fuses completely 

 with the larval skull and then separates from it again by the ingrowth 

 of connective tissue, but this secondary segmentation occurs a little 

 lateral to the point of the original fusion, so that a portion of the 

 primitive proc. basalis is left fused to the capsule and forms the base 

 of the canal through which the facial nerve emerges — the facialis 

 canal. The now secondary proc. basalis — which is the only part 

 recognizable in the adult — is thus separated from the primary portion 

 by connective tissue, and the most convenient way to dissect the 

 antrum petrosum laterale, in order to examine its contents, is to 

 disarticulate this junction from the ventral side, when the whole sus- 

 pensorium may be turned back, and, after breaking through the 



