DESCRIPTION OF PLATES. 825 



Pig. 13. Bete mirabile seen through the epidermis of the funnel-organ in the fresh state. 



Fig. 14. Portion of endochondral sinus showing a valve arching over the capi to-pedal 

 orifice. An arrow is passed from the tubular sinus in which the levator muscle of the funnel 

 lies, into the endochondral sinus. 



c. Cartilage. 



v. Valve. 



Fig. 15. Ovarian ovum of an injected specimen, removed from the body and viewed 

 from the animal pole showing the ramifications of the genital artery in the follicle. 

 Fig. 16. Enlarged view of portion of preceding. 



Fig. 17. Section through an ovarian ovum, showing the intra-lecithal processes of the 

 follicle. 



Fig. 18. Abnormal egg of J¥. macromphalus, with defective capsule exposing the vitellus 

 at three places. The outer capsule was only present on one side of the egg, namely, on 

 the side opposite to that figured. 



Fig. 19. Inner capsule of an egg of N. ponipilius from below, showing clear mesial 

 longitudinal tract separating the striations of the remaining surface. The outer capsule has 

 been removed except in the region of its median and lateral attachments to the inner capsule. 



Fig. 20. Pear-shaped inner capsule of egg of JV. macromphalus from below. The outer 

 capsule has been removed except at the hinder end in the region of the irregular disc of 

 attachment which presents a spongy cavernous surface. The striations of the inner capsule 

 tend to run longitudinally below and transversely on the upper side of the egg. 



Fig. 21. Egg of N. macromphalus from above, with the longitudinal slit in the upper 

 wall of the outer capsule widened out so as to expose the inner capsule with its striated 

 surface. Eeproduced from P. B. Soc. London, Vol. lx. 1897, p. 470, fig. 4. 



Fig. 22. N. macromphalus. Inner capsule of egg seen from below (i.e. from the side 

 directed towards the disc of attachment). Half the lower wall of the capsule has been 

 removed by slitting along one of the lateral sutures and along the median groove (depressed 

 longitudinal tract) to show the brown-coloured vitellus lying in the capsule. The lateral 

 sutures are continued into each other at the front of the capsule so that the inner capsule 

 is really bivalvate. The germinal disc (not indicated) occurs at the anterior pole of the 

 vitellus, the orientation of the laid egg coinciding with that of the ovarian egg (cf. text- 

 fig. 13). 



Fig. 23. N. macromphalus. Inner capsule of egg in side view, showing the dorsal 

 ridge with its anterior terminal process and the lateral suture. A fragment of the outer 

 capsule remains at the hinder end, the rest having been cut away. 



Fig. 24. Enlarged view of one of the nascent tentacles of the extrabuccal series shown 

 in PI. LXXX. figg. 1 and 2. 



The tentacle appears as a minute papilla and the sheath seems to grow round it as a 

 dermal fold with a simple border in front and a deep notch (possibly indicating concrescence 

 of the two halves of the fold) at the back of the tentacle. Zeiss 3 A. 



Fig. 25. Macroscopic view of the eye in vertical section. The plane of section lies 

 on one side of the pinhole aperture so that this is seen intact from the interior of the 

 optic cup. The bacillary layer representing the vitreous body forms a thin sheet over the 



