THE CENTRAL ACOUSTIC LOBE 



63 



for the bleak, the fresh-water sprat. We have described the small 

 easily detached scales and the abdominal keel as being present in 

 these fish and that the eyes are large. It is very instructive to be 

 able to point out the similarity in the brain pattern in the fourth 

 group of carps and the Clupeoids. 



We have described the large central acoustic lobe or area and 

 its association with a small type of facial lobe which in both families 

 does not appear on external observation. The optic lobes are also 

 well developed. The vagal lobes are also feebly developed. We 



Fig. viiA. 



Fig, viiB. 



Fig. vHa. — The central acoustic lobe of the sprat. It has been cut rather obliquely. 

 This lobe occupies a large area of the cerebellum. The acoustic tubercles are 

 prominent and the lateral line nerve is seen externally passing into it. The 

 eighth nerve is also seen. 



Fig. viiB. — Transverse section of cerebellum of PUchard to shew central acoustie 

 lobe, c.e.l. s.g. and s.m. — Strata granulosa and moleculare of cerebellum. 

 V lobe. — Somatic sensory lobe. 



have here a striking example of the correspondence of general form 

 and habits of feeding with the pattern of the brain. Another point 

 also seems to be worth mentioning, namely, that the relative size 

 of the central acoustic area varies inversely with the relative size 

 of the facial lobes. In a later chapter we shall be able to show that 

 the central acoustic lobe appears to be well developed in other 

 families of fish in which the faculty of hearing is of considerable 

 importance in their life history. 



If the dominant fresh-Mater fishes of the British Isles had been 

 the MormjTidae instead of the carps, the attitude of the scientist 



