Hekchman. — Nervous System of Limax. 



PLATE m. 



Figs. 25-27 are from the same individual {ninth day) as Figs. 20-24 on Plate II. 

 They are magnified 83 diameters. 



" 25. This section passes through the left cerebral gangUon, and the cerebral 

 invagination of the right side. 



" 26 shows, in addition to the cerebral invagination, that of the right eye (at 

 the left of the figure). 



" 27. Section passing through the pedal ganglia and their anterior commissure. 

 It shows a cross section of the oesophagus, the radula sac, and the right 

 otocyst. 



" 28-31. The left surface of sections parallel to the sagittal plane from an em- 

 bryo of the tenth day. (Figs. 58, 59, Plate IV., and Figs. 61, 63, Plate 

 v., also belong to this series.) This individual was killed in Perenyi'a 

 fluid, and stained in picro-carminate of lithium. X 100. 



" 28 and 29 are successive sections passing through the invaginations of the cere- 

 bral ganglion and the eye of the left side. 



" 30 shows a cross section of the cerebral commissure. 



" 31. The second section nearer the median plane than Fig. 30, showing the 

 cerebral commissure, the position of the right visceral ganglion, and 

 the anus already open to the exterior. 



" 32-47, 51. The left surface of sections cut parallel to the sagittal plane, from 

 an embryo of the eleventh day, magnified 100 diameters. Killed in 

 Perenyi's fluid, stained in Czoker's cochineal. (Sections shown in 

 Plate V. Figs. 62, 64, 67, and Plate VI. Figs. 70-73, also belong to 

 this series.) 



" 32-38. Seven successive sections passing through the invagination for the 

 cerebral ganglia of the left side. 



" 39. The second section nearer the median plane than Fig. 38, showing the 

 inner sac-like end of the invagination. 



" 40. The next section, showing the blind end of the invagination and the 

 proliferated portion of the ganglion. 



" 41 and 42. Successive sections (32d and 33d of the series) passing through the 

 left pedal ganglion and the connective between the abdominal and 

 left visceral ganglia. 



" 43. Section cutting the abdominal ganglion crosswise. 



" 44. The 35th section shows, in addition to the abdominal ganglion, a cross 

 section of the anterior pedal commissure. (The 36th, 37th, 39th, and 

 40th sections of the series are sliown in Figs. 47, 46, 45, and 51, 

 respectively.) 



" 45. Section passing through the connective between the abdominal ganglion 

 and the right visceral ganglion. 



" 46 sliows the abdominal ganglion still connected with the ectoderm. 



" 47. The next section to that shown in Fig. 44, passing through the abdominal 

 ganglion. 



" 48, 49. The left surface of sections cut parallel to the sagittal plane from an 

 individual of about the twelfth day, magnified 100 diameters. Killed in 



(See obverse.) 



