3IO Susanna Phelps Gage 



Fig. 57. Transection of the nierlulla of a larval diemyctylus, 16 ram. 

 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 habena;, 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 habeas ; the post- 

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

 of 59- 



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 bj' Golgi's method. X 120. Shows the fine filaments .ar 

 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 cerebnim and thalamus with fila- 

 ments X extending to the vessel. 



PLATE VI. 



As in Plate II cinerea extending to the surface is shown bj' 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 ner\'es. 

 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 habense ; 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 mesoccele. 



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 7^ ; 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, pcni ; the unde- 

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

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



