3IO " Susa7ina Phelps Gage 



Fig. 57. Transection of the medulla of a larval diemyctylus, 16 mm. 

 long, near the level of 88 Fig. 67. X 27. Two or three cells from the 

 endyma are lacking at the metapore (of. Fig. 55). 



Fig. 58 60. Parts of frontal sections from the same series as Fig. 35. 

 See 60 Fig. 6. X 125. Fig. 58 shows the epiphysis cephalad of which is 

 the cinerea of the habente, and caudad are blood vessels. Fig. 59 shows 

 the paraphysis surrounded by vessels of the supraplexus, dura arach- 

 noid and pia ; the supracommissure connecting the habenae ; the post- 

 commiSsure with fibers from the cells of the ''torus." Fig. 60 is ventrad 

 of59- 



Fig. 6r. Part of a transection of the brain of an adult, female, die- 

 myctylus 1 1.5 cm. long, from the dorsal part of the geminum (cf. Fig. 

 25), prepared by Golgi's method. X 120. Shows the fine filaments x 

 from the brain surface extending toward the pia ; cells among the fila- 

 ments with processes into the alba ; processes connecting with 

 endymal cells and cells scattered in the alba, and separating the cells 

 of the cinerea in rows. These are a few selected fibers from the mass. 

 In some cases fine processes apparently connect the ectal and ental set 

 of fibers. 



Fig. 62. A part of a frontal section enlarged from x Fig. 69. X 500. 

 Shows a blood vessel between the cerebrum and thalamus with fila- 

 ments X extending to the vessel. 



PLATE VI. 



As in Plate II cinerea extending to the surface is shown by dots, 

 upon cut edges, by cells ; interrupted lines indicate extent of cavities. 



Fig. 63-65. Reconstructed views of the brain of a larval diemyctylus 

 10 mm. long (Fig. 12), and 2-3 days after hatching. X 56. 



Fig. 63. Ventral view (cf. Fig. 3), shows the great breadth of the 

 brain in the region of the epencephal, completely hiding the mesence- 

 phal ; the small hypophysis ; the deeply lobed gasserian ganglion, and 

 the separation of the ganglia of the 7th, 8th, 9th, and loth nerves. 

 The 6th is somewhat exaggerated in size, and a nerve is shown caudad 

 of I2th, probably the ist spinal. 



Fig. 64. Dorsal view (cf. Fig. 4) shows the short cerebrum overhung 

 by the habenae ; the relatively large diencephal and mesencephal ; the 

 extensive areas of cinerea ; the cephalic projection of the epencephal 

 with its membranous roof, ep ; the caudal expansion of the mesocoele. 



Fig. 65. Lateral view (cf. Fig. 5). The origin of nerves is left white ; 

 shows the comparatively ventral position of 5th and 8th, and the long 

 axis of the porta extending cephalo- caudad with the paraphysis open- 

 ing at the caudal margin. 



Fig. 66. Part of a sagittal section of the head near the meson of a 

 larval diemyctylus, 12 mm. long. X 60. Shows the relation of the para- 

 physis to the plexus and the commissures (cf. Fig 7I ; the small amount 

 of tissue between the brain and the skin and mucosa. 



Fig. 67. Mesal view of same as Fig. 63. X 130. (cf. Fig. 6). Shows 

 the large aula, the small cerebral commissures, cal, pan ; the unde- 

 veloped supraplexus ; the paraphysis, pushed cephalad by the habenae, 

 the endymal character of the roof of the mesencephal with a more 



