1876.] Mr Bettany, On ike Primary Elements of the SIcull. 5 



in continuity with the parachordals : and in these lateral walls 

 nerve foramina occur in precisely the same way. In fact every 

 relation of the trabecule proper is neural. Accepting the morpho- 

 logical identity of the trabeculse with the parachordals, they may 

 either be regarded as truly axial, or as the basal parts of proper 

 neural arches ; the latter view would seem to cause great difficulty 

 in accounting for the basioccipital, basisphenoid, and presphenoid 

 bones. Assuming the trabeculse to be axial or neural elements, 

 one might expect more or less definite appendicular pieces to be 

 found in relation to them. The mandibular arches have a primary 

 relation to the hinder part of the trabeculse ; while the antorbital 

 or lateral ethmoidal (with its frequently distinct antorbital car- 

 tilage), the cornual and the prenasal regions offer developments 

 which may with some reason be considered as appendicular. On 

 this view the orbitonasal nerve would be accounted for : the tri- 

 geminal nerve might be regarded as a nerve of several segments 

 like the pneumogastric : its branches being distributed along the 

 cornua, over the ethmoidal region on either side, and on the pala- 

 topterygoid and the mandibular tracts. The relations of the sense 

 organs to the axial parts are very strange if the trabeculse are 

 visceral arches ; while they seem more intelligible when they are 

 regarded as paraxial elements, the olfactory organs situated be- 

 tween the cornual and antorbital regions, the eyes between the 

 antorbital and mandibular, the ears between the mandibular and 

 hyoid. 



In conclusion, I would submit that the doctrine of the tra- 

 beculaB being visceral arches presents so many difficulties, that it 

 ought not be adopted without the strongest evidence in its favour: 

 the counter-view is urged as more natural and simple, as well as 

 more in accordance with facts. 



November 6, 1876. 

 Pkof. Clerk Maxwell, F.R.S., President, m the chair. 



The following Communications were made to the Society by 



(1) Mr J. W. L. Glaisher, M.A., F.R.S., On a Formula of 

 Cauchy s for the Evaluation of a class of Definite Integrals. 



In his Memoir "sur une formule relative a la determination 

 des integrales simples prises entre les limites et oo de la 

 variable" {Exercices des Maihematiques, t. l. -pp. 54 — 56, 1826) 

 Cauchy has given his now well-known evaluation of the integral 



/>/(.- l)rf., 



