14 



NERVE COMPONENTS OF BONY FISHES, 



system of sense organs as well (Text-figure 3, ta.). 

 A comparative study reveals the fact that this centre 

 varies in size with the degree of differentiation of the 

 lateral lines. 



Thus, in the sturgeon, whose other medullary centres 

 are relatively feebly developed, this system is greatly 

 enlarged and a portion of it has been differentiated in 

 front to form the lobus lineas lateralis of Johnston (Text- 

 figure 4, /. /.), the so-called lobus trigemini of the older 

 authors. 



Text-Figure 4. 



Text-Figure 4. — The brain of the sturgeon, Acipenser, as seen 

 from above. After Goronowitsch. /./. — lobus Hneae lateralis; 

 other letters as before. 



This acustico-lateral centre, like the vagal lobe, is 

 difficult to correlate with anything found in the spinal 

 cord. 



These cases, and many others which might be given, 

 illustrate the way in which comparative anatomy assists 



