Henchman. — Nervous System of Limax. 



PLATE IV. 



All figures of this plate magnified 250 diameters. 



Figs. 53, 56, 57, and 55 are four successive sections from the same embryo. This 

 was seven days old, but much more advanced than the embryos represented 

 in Figs. 6-13, 15, 17, and 18. Killed in 0.33% chromic acid, stained in 

 alcoholic borax-carmine. 



" 53. Posterior face of a transverse section passing through the visceral ganglia, 

 the external opening of the nephridial organ of the right side, and the 

 opening into the mantle chamber or respiratory cavity. (Compare 

 Figs. 56 and 55.) 



" 54. The posterior surface of a transverse section passing through the anterior 

 pedal commissure. Embryo of about the same stage of development 

 as the preceding, and prepared in the same way as that. 



" 55. Portion of the third section following that shown in Fig. 53 ; it passes 

 through the pedal and visceral ganglia of the right side. 



" 56 shows both the visceral ganglia. 



" 57. Portion of section showing the left pedal ganglion and cell proliferation 

 from the ventral wall of the foot ; the visceral ganglion and the ex- 

 ternal opening of the nephridial organ of the left side are also seen. 



" 58, 59. Consult explanation of Figs. 28-31, Plate III. 



" 68. Sagittal section passing through the proliferated portion of the right 

 cerebral, pedal, and visceral ganglia and right otocyst. Shows cell 

 proliferation from the ventral wall of the foot, and that the visceral 

 ganglion is attached to the ectoderm at the margin of the mantle 

 cavity. 



" 59. A small portion of the section following Fig. 68 to show the right visce- 

 ral ganglion and its attachment to the ectoderm. 





