220 JOHN BEARD. 



Fig. 3. Transverse section of olfactory organ (olf.o.) and nerve {olf.n.) 

 in Rana temporaria. Z. c, oc. 2, cam. luc. 



Fig. 4. Transverse section of embryo of Rhodeus amarus, showing 

 olfactory nerve and thickening both fused with skin. 

 Letters as before, f.br. Brain. Z. p, oc. 2, cam. luc. 



Fig. 5. Transverse section through fore-brain and olfactory organ of 

 an embryo of T. ocellata. Combined from several sections. 

 Shows olfactory nerve and ganglion fused with thickening 

 and connected with brain. Letters as before. Z. a, oc. 2, 

 cam. luc. 



Fig. 6. Somewhat horizontal section through mid-brain, showing 

 nerve of ciliary ganglion (n.c.gl.) just fusing with skin. 

 T. ocellata. Z. f, oc. 2, cam. luc. 



Fig. 7. Low-power view of same section. Z. c, oc. 2, cam. luc. 



Figs. 8 & 9. High- and low-power drawings respectively of a some- 

 what horizontal section through fore- and hind-brain. 

 Shows ciliary ganglion rudiment (c.gl.) and its primitive 

 branchial sense organ (p.br.o.). The ganglion is in course 

 of formation from the epiblast. f.br. Fore-brain. 7i.br. 

 Hind-brain. Torpedo ocellata. Z. D and a, oc. 2, cam. luc. 



Fig. 10. Horizontal section through a young Torpedo embryo, showing 

 ciliary ganglion still fused with its sensory thickening. 

 Also shows motor oculi nerve, (in), c.gl. Ciliary ganglion. 

 p.br.o. Primitive branchial sense-organ, in. Motor oculi. 

 G.gl. Gasserian ganglion, hy.cl. Hyoid cleft, m.br. Mid- 

 brain, h.c. Head-cavity, f.gl. Facial ganglion. Z. a, oc. 2, 

 cam. luc. 



Fig. 1 1 . Drawing under high power of ciliary ganglion and its primi- 

 tive sense organ of the preceding section. Late stage, 

 but still intimate fusion with skin. Also origin of supra- 

 branchial nerve of ciliary ganglion (ophth. profund.) from 

 skin. Supra - branchial nerve (s.br.n.). Z. F, oc. 2, 

 cam. luc. 



Figs. 12 & 13. Similar drawings to figs. 10 and 11 respectively. Let- 

 ters as before, gl.gl. Glossopharyngeal ganglion. 



Fig. 14. Horizontal section through mid-brain and anterior portion of 

 hind-brain. Shows course of fifth nerve, which lies just 

 under skin, but is not yet fused with it. No ganglion yet 

 present. T. ocellata. Z. 0, oc. 2, cam. luc. 



