30S G. E. COGHILL 



Figs. 1 to 4 Graphic projections from serial, transverse sections upon the 

 median plane to show the ganglia and sensory nerves of the head in the four 

 physiological stages: 



Fig. 1 (No. 467), the non-motile. 



Fig. 2 (No. 473), the early flexure. 



Fig. 3 (No. 449), the coiled-reaction. 



Fig. 4 (No. 444), the early swimming stage. X 50. 



The brain is drawn in heavy lines; the myotomes and sense organs, in light 

 lines; the general somatic sensory ganglia, in stipple; the lateral line and auditory 

 ganglia, in diagonal lines; the visceral sensory ganglia, in rectangular cross- 

 hatching. The lateral line nerves are not fully represented here. They follow 

 the course of the lateral line primordia, the distribution of which is shown in 

 Paper I, figures 56 to 59. These, figures with the descriptions in the text of this 

 paper will give the important features of the lateral line nerves in the stages 

 described. Silver impregnations of the early swimming stage show that these 

 nerves are practically coextensive with the primordia of the organs. This is 

 probably true of the earlier stages also, although satisfactory impregnations of 

 the fibers have not yet been secured. The ganglia and sense organs have been 

 projected mechanically with great care. The nerve trunks, which are too small 

 to project distinctly at the magnification which has been used, have been sketched 

 free-hand. 



