IO2 Animal Morphology. 



perception of one or the other, as their particular cerebral 

 impressions and anastomosis with each other in the great 

 central sensient mass may impose upon each individual 

 sense.* 



Certain senses, as the optic and acoustic, appear to be 

 specially free from any marked changes of temperature, 

 saving during fevers, etc., when their functions, with that of 

 the cerebral mass, frequently suffer considerable change. 

 Also from indigestion, and the presence of certain acids 

 and other compounds in the stomach and bowels, unpleasant 

 sensations of heat are experienced, the result of impressions 

 on the periphery of the par vagum, etc. 



OWEN considered that the special senses carried with them 

 certain anatomical peculiarities which entitled them to the 

 nomenclature of sense capsules. 



It is almost a pity to alter nomenclature to fit it to any 

 special theory, or new explanation ; but inasmuch as capsule 

 is too circumscribed in its application for the present subject,, 

 the nomenclature of sense apparatus though rather indefi- 

 nite in its signification, will be used in preference to sense 

 capsules, for it is sufficiently expansive to admit any of the 

 senses into its category of objects. 



Leaving, then, the precise object for which, in the diffe- 

 rentiations of the notochord, the nomenclature of the arches 

 is adopted, as that of the haemal and neural arches, it is 

 here assumed that these arches are the apparatuses of three 

 senses the senses offeree, touch, and want, the two former of 

 which inosculate and intersperse with each other at several 

 points, though at no point do they amalgamate so as to consti- 

 tute one sense ; but they frequently occupy the same ground, 

 or area of surface, by the interpenetration of their fibres. So, 



* Edinburgh Medical Journal, 1859, p. 797. 



