FISH IN GENERAL. 71 



We have thus far endeavoured to give a very epitomized 

 view of the skeleton and muscles, not without fear that where 

 so much is sacrificed to brevity, the subject may not be found 

 sufficiently clear to those who have not made comparative 

 anatomy a study ; yet our limits compel us to be even more 

 concise on the remainder of this part of the science. 



THE BRAIN. 



The brain of fishes is remarkably small in proportion to the 

 bulk of the animal, the quantity of nerves arising out of it, 

 and the size of the cavity that contains it. The space thus 

 left vacant is often filled with a kind of soft cellulosity, or even 

 with oil or fat. In young fish it is not so considerable as in 

 adults ; whence the inference is drawn, that the brain does 

 not increase in bulk, in proportion to the enlargement of the 

 cavity. The lobes of the encephalon are placed behind each 

 other, often representing a kind of double chaplet ; there are 

 also tubercles, concealed within or beneath the great lobes. 

 The cerebellum is placed transversely upon the medulla, and 

 before it on the superior surface is seen a pair of lobes always 

 hollow internally, before which there is found a second, and 

 often a third pair of other lobes, generally solid. In the inte- 

 rior of the hollow lobes before the cerebellum, one or two pairs 

 of tubercles are usually placed ; and on the inferior surface of 

 the same part, under the hollow lobes, there is another pair of 

 protuberances, which we name the inferior lobes, having be- 

 fore them the pituitary gland. Behind the cerebellum are 

 other lobes, differing in number and form, and without evident 

 corresponding parts in the superior classes of animals ; per- 

 haps the nearest analogy is with the olivary bodies, than 

 which, however, they occupy a higher situation. These we 

 name posterior lobes. The relative size of the cerebellum is 

 rather considerable, and often surpassing in volume the parts 

 placed before it, and having either no lateral lobes, or only 



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