PLATE III. (continued.) 



0.33% chromic acid, and stained in alcoholic borax-carmine. (Sec- 

 tions shown in Plate V. Figs. 65, 66, and Plate VII. Figs. 81, 82, also 

 belong to this series.) 

 Fig. 48. A section passing through the cerebral and pleural ganglia of the right 

 side, and also through the abdominal ganglion. 



" 49 shows the proliferated portion of the cerebral ganglion and the visceral 

 ganglion of the right side. 



" 51. (See explanation of Figs. 32-47.) The section following that shown in 

 Fig. 45. It passes through the connective between the abdominal 

 ganglion and the visceral ganglion of the right side. 



" 50, 52. The posterior surface of transverse sections of an embryo at the same 

 stage of development (twelfth day) as that represented in Figs. 48 and 

 49. The ventral portion and the right side cut a little in advance of 

 the dorsal portion and the left side, magnified 100 diameters. Killed 

 in 0.33% chromic acid, stained in alcoholic borax-carmine. 



Figs. 85-94, Plate VII., continue this series. The following shows 

 the sequence of the sections : — 

 Section 77, 101, 103, 109, 110, 112, 113, 117, 125, 126, 128, 146. 

 Figure 90, 92, 91, 93, 50, 52, 85, 86, 88, 87, 89, 94. 



" 50. This section passes through the left pedal ganglion and the abdominal 

 ganglion where the latter is still attached to the ectoderm. The 

 mantle cavity open to the exterior. 



" 52. The second section in front of Fig. 50, showing that in this region the ab- 

 dominal ganglion is free from the ectoderm. 



