Terry — The Nasal Skeleton of Amhlystoma punctatum. 113 



ethmoidjil plate as already pointed out. In no stage except 

 the adult were intermaxillary glands present. It is easy to 

 observe how, in Amblystoma, the disproportion in the longi- 

 tudinal growth of the brain and ethmoidal skeleton results in 

 the final relations of these organs. Concerning the forma- 

 tion of an internasal space, Gaupp ('05.1) has suggested 

 the influence of cover bones in this region. 



In the four stages modeled the trabeculae have a constant 

 relation to the nasal organs. The trabecular plate, and so 

 far as I am able to determine from my material and from 

 the literature, the Cornua are developed in connection with 

 the trabeculae, as is also the anlage of the rod (Col. eth.). 

 The Crista, as has been shown, gains its relation to the nasal 

 sac secondarily. The relations of the trabecula to the mouth 

 do not concern us in the present work. 



The development of the cartilaginous nasal skeleton of 

 Amblystoma is comparable in many respects with the processes 

 in Triton as described by Born ('76). The changes in the 

 position of the nasal sacs and the formation of an internasal 

 space are very similar in the two. The origin of a cartilag- 

 inous mesal nasal wall from the trabecula and the subsequent 

 growth of the nasal capsule from the same are conditions not 

 actually met with in Amblystoma. The anlage of the rod 

 (Col. eth.), it is true, is in connection with the trabecula and 

 it is in connection with the rod that a large part of the capsule 

 arises, including a medial nasal wall. The cartilaginous rod 

 does not chondrify from the trabecula out, but spreads to- 

 ward it. However, this independent chondrification of the 

 rod does not mean that genetically it has nothing to do with 

 the trabecula ; the anlage indicates a close relation between 

 the two and so it appears to me that there is after all not 

 much difference in the origin of the capsule in these two 

 animals. In larval Amblystoma a proper medial nasal wall is 

 present only for the anterior part of the olfactory sac ; it 



