Royal Irish Academy, 487 



tlie adhesions between them, he is induced to attribute these ad- 

 hesions, by which the ascent of the extremity of the cord to its 

 usual position was prevented, to the irregular manner in which the 

 nerves had become inserted in the spinal marrow. 



3. That the union of the ganglia may be in some measure 

 ascribed to the development of a process by which the ad- 

 joining ganglia are in some instances, even of normal conforma- 

 tion, connected with each other, and that the general occur- 

 rence of the deformity at the lower extremity of the spinal column 

 may be attributed to the relative position of the sacral ganglia, 

 which are placed within the sacral canal, those of the other spinal 

 nerves being placed in the intervertebral foramina. 



4. That the incomplete formation of the posterior wall of the 

 spinal column is rather to be attributed to the interference occa- 

 sioned by the irregular development of the corresponding part of 

 the nervous system than to any peculiar defi(^iency in the process 

 of ossification. 



ROYAL IRISH ACADEMY. 



December 12, 1836. — A paper was read ** On the Seals of Ireland 

 (Phocidse)." By Robert Ball, Esq., M.R.I.A. 



The author stated the circumstances by which he was led to dis- 

 cover that the seal of most frequent occurrence on the Irish coast 

 was not defined as a British species, together with the subsequent 

 identification of that animal, by Professor Nilsson, as the Halichcerus 

 griscus of his Scandinavian Fauna, (Phoca Gryphus of Fabricius,) 

 found in the Baltic and North Sea. He asserted, however, that the 

 habits of the Halichaerus of this country differed so much from those 

 ascribed to it in the Baltic, that it appeared to him not unlikely, on 

 comparison, to prove a distinct species. He showed that the co- 

 lour of the animal here varied so much from sex, age, season, &c., 

 that it could not be considered of anyvalue as a character of species 

 in the present state of our knowledge of the subject. He alluded 

 to the very small size of the brain compared with that of the genus 

 Phoca, and stated that the intellectual powers bore the same pro- 

 portion. Mr. Ball then proceeded to show that the simple form of 

 the teeth of Halichaerus (approaching closely to those of some 

 species of Delphinus) furnished suflGcient grounds for separating it 

 from the genus Phoca ; and observed, that the Halichaerus may 

 always be distinguished from other seals, by its straight profile, fierce 

 aspect, and greater proportionate length. He mentioned the fact 

 of his having discovered that the specimen in the British Museum, 

 so long known as Donovan's Phoca barbatat (and the long-bodied 

 seal of Parsons,) is formed of the skin of a Halichaerus improperly 

 stuffed ; and he noticed the mistakes to which this has given 

 origin. 



Mr. Ball next gave instances of the occurrence in this country of 

 the Phoca Vitulina (P. variegata, Nilss.), which he considered iden- 

 tical with the seal stated by Sir E. Home (Phil. Trans. 1822) to have 

 been killed in the Orkneys, though it appears from the cranium 



