20 PROCEEDINGS OF SOCIETIES'. 



several anatomists ; but the theory was, for the first time, carried out in all 

 its details, by Okcn, and since his views were promulgated, we have had as 

 many theories as writers. The object of Dr. Scouler's Lecture was, to ex- 

 hibit what appeared to him the difficulties which opposed themselves to the 

 vertebral theory ; and in doing so, he observed, in the first place, that there 

 ensued the greatest discrepancy among the defenders of the vertebral theory 

 as to the number of vertebrae of which the cranium is composed, — some con- 

 tending for three, while others increase their number to seven. Wliatever 

 number we may assume, there is one objection which may be made to them 

 all, viz., that the number of bony elements is not invariable in the crania of 

 animals, — some having more, some fewer distinct bones. Thus the bones of 

 the operculum are found only in fishes ; and even the number of opercular 

 bones is not the same in all fishes, — the numerous family of Siluroids hav- 

 ing only three, while the greater number of fishes have four. Even the 

 same bone performs different functions in different animals. Thus the 

 squamous portion of the temporal in man, protects a part of the brain, and 

 in him must be a portion of a cranial vertebra ; while in the inferior animals 

 it is excluded from that function. In like manner the mastoid, which is a 

 portion of the temporal in man, becomes unimportant in the inferior ani- 

 mals ; while on the other hand, we find in them a mastoid which is a portion 

 of the occipital. 



The Doctor further objected, that the brain differed from the spinal mar- 

 row, not only in its greater size, but also by containing many parts which do 

 not exist in any portion of the spinal marrow ; nor is it legitimate to sup- 

 pose, that there should be no corresponding difference in the composition of 

 the bony protecting parts. The nerves which proceed from the spine are 

 merely motive and sensitive, while from the brain proceed also olfactory, 

 optic, and acoustic nerves ; and all the bony parts which protect these must 

 be excluded from the composition of a vertebra. When these parts are ab- 

 stracted, it will be difficult to construct a series of cranial vertebrae. 



Even the spinal vertebrae themselves, to which we have to assimilate the 

 cranial ones, present many difficulties in the way of this theoiy, for the 

 number of bony elements vai'ies in the spinal vertebrae in different animals, 

 and even in the same animal the composition of a vertebra differs in dif- 

 ferent parts of the spinal column. 



Business being concluded, a vote of thanks was passed to Dr. Scouler, and 

 the meeting adjourned to October. 



Oct. 5rd. The ordinaiy Monthly Meeting was held this evening, J. P. 

 Fbaseb, Esq., F. G. S., President, in the Chair. 



On the conclusion of the opening business, the President, with much 

 feeling, announced to the members the sudden removal, by death, of one of 

 theii- corresponding members, Dr. Landsborough, of Saltcoats. " Gentlemen, 



