The Brahi of Dieniydylus Viridescens 307 



nerve, the ytli continuous with cinerea and also receiving fibers ; fibers of 

 the 8th crossing the meson. 



Fig. 9, 10. Dorsal parts of transections of the brain of adult diemycty- 

 lus, stained in carmine. X 65. Fig. 10 is caudad of 9, at the level between 

 23 and 24 of Fig. 6. They show the membranes passing dorsad of the 

 epiphysis, but the vessels of the pia surround it, and do not cross the 

 meson. The fibers of the postcommissure are mingled with fibers which 

 apparently arise in the peculiar cells of the roof called torus, (cf Fig. 

 59, 60 and p. 266). 



Fig. II. Lateral view of adult diemyctylus, male, nearly natural size, 

 (16). I, the pockets at the side of the head (cf. Fig. 40). 



Fig. 12. Shows length of the larva, the brain of which is represented 

 in Plates I and VI. 



PLATE III. 



A few of the sections from which figures 3-6 were reconstructed. 

 Their position is shown in figure 6 by corresponding numbers. The 

 membranes and capillaries are shown at the left, and the position of eye, 

 ear and nostril indicated. The cinerea is represented by dots. X about 

 22 (see scale). 



Fig. 13. Near the tip of the olfactory lobes, showing the cells ar- 

 ranged in rows perpendicular to the niesal surface, the first root of 

 the olfactory nerve I, and the intermaxililary gland. 



Fig. 14. Through the second olfactory nerve roots I^. Cells are con- 

 tinuous from ectal to ental surface. 



Fig. 15. Near the boundary between olfactory lobes and cerebrum. 

 At olf. are cells continuous with those belonging to the olfactory re- 

 gion ; at ce. the beginning of the callosal eminence ; at t. cells which 

 mark the caudal path of the terma (p. 282), and are just cephalad of the 

 portae. 



Fig. 16. The paracoeles are separated only by the crista and a double 

 layer of endyma, a part of the terma. The striatum is represented by 

 the part lying between the two lateral projections of cinerea. 



Fig. 17. At the level of the portae ; the hemicerebrums are united 

 dorsally only by the pallium with its plexuses. 



Fig. 18. The callosum lies between the aula and preoptic recess. 



Fig. 19. Shows the lateral columns of the callosum extending to the 

 cerebral eminence, and the auliplexus caudad of the paraplexuses. The 

 striatum shows scattered cells connecting the two horns of cinerea. 

 The caudal horn of the paracoele is fully established by the union of 

 the mesal and lateral walls of the cerebrum. 



Fig. 20. Through the supraplexus and optic nerves II, which extend 

 cephalad and enter the eye at the level of figure 17. 



Fig. 21. Through the opening of the paraphysis. Compare relations 

 of thalamus and paraphysis with figure 98. 



Fig. 22. Through the tip of the cerebrum containing Amnion's horn. 

 A recess of the epiphysis expands dorsad of the habenae while ventrad 

 of them are the sulci continuous with pi of the next cephalic sections. 

 The two plexuses appear. 



