75 



Fig. 2i. Dissection of niantl'j nerves in posterior region to 

 show the anastomosis {Z) between the posterior 

 palhal nerves {P.PalX.) of the two sides. The 

 dissection is supposed to be made from the 

 ventral surface, and a small portion of the skin is 

 left to show the pallial tentacles (see also Fig. 8). 

 X 8. (After a drawing by J. T. Jenkins). 



Fig. 25. Longitudinal section of the cephalic tentacle. 7'..V. = 

 Tentacular nerve, x 15. 



Fig. 26a. Section of eye epithelium, x 800. 



Fig. 26/>. Pigment cell of eye epithelium, x 1,500. 



Fig. 26c. Sense cell of do. S.C. = Sense cell. I'.C. = Pig- 

 ment eel'. P.Z. — Pigment zone, x 1,500. 



Fig. 27a. Section of otocyst and nerve (after de Lacaze- 

 Duthiers). x 15. 



Fig. 27b. Epithelium of otocyst cavity. 



Fig. 28. Section of osphradium, etc. OspJi.G. = Osphradial 

 ganglion. Os.7'.\ = Osphradial epithelium. li.G. 

 = Eudimentary gill (ctenidium). x 180. 



Plate IY. 



Fig. 29. Heart of Patella. N.B.V. = Veins from the nuchal 

 roof. Ant.Ao. = Anterior aorta. L.Au. = 

 Auricle (morphologically left). Post. A. = 

 Posterior artery. Vn. — Ventricle, x 3. 



Fig. 30. Eight kidney (after Lankester). A.-D.Lohc = A.niero- 

 dorsal lobe. P. -V. Lobe = Peri-visceral lobe. 

 S'.-i?.Loic = Sub-rectal lobe. V.Lobe — Ventral 

 lobe. X 1^. 



Fig. 31. Diagrammatic transverse section showing the position 

 of the renal aperture (B.B.P.) of the renoperi- 

 cardial canal of the right kidney. The anterior 

 face of the section is drawn, x 80. 



Fig. 32rt. Diagram illustrating the structure of the kidney. 

 K.C. = Kidney cavity, x 300. 



