886 PROF. G. C. BOURNE ON THE [Nov. 17, 



Plate LV. 



Fig. 3o. View of the pharyngeal bulb and alimentaiy tract of JST. {Paranerifa) 

 longispina unravelled. 



36. A dorsal view of the pleuro-pedal nerve-centres and principal nerves 



issuing from them in ISf. {Paranerita) gagates. The lettering in this 

 and the succeeding figures is the same as that adopted bj' Bouvier (9). 

 Gd. Right pleural ganglion. Cg. Left pleural ganglion. O. Otoeyst. 

 P. Pedal centres. 6^. Left symmetrical branchial nerve. rZ^, cP-. Anterior 

 pallial (parietal) nerves of the right side, e^, e"-. Anterior pallial (parietal) 

 nerves of the left side. li. Supra-intestinal nerve, li^. Subintestinal 

 nerve, k^. Cerebro-pedal connective, li-. Cerebro-pleural connective. 

 Id. Right columellar nerve. Ig. Left columellar nerve, m. Pallial 

 branch of the left brancbio-pallial nerve, m^. Right pallial nerve. 

 o'p. Opercular nerves, issuing from the upper surface of the pedal centres. 

 s. Branches of the cerebro-pleural connectives passing to the walls of the 

 head. Bh. Subintestinal ganglion. 



37. A section taken somewhat obliquely through the pleural and pedal centres. 



2. Origin of the lower of the two direct commissural connections between 

 the pleural ganglia. Z. Zygoneurous connection between the right 

 pleural ganglion and the subintestinal nerve. Other lettering as in 

 tig. 36. 



Plate LVI. 



Fig. 38. A section through the pleural centres posterior to that shown in the 

 preceding figure. 1 & 2. Upper and lower direct commissural connections 

 between the pleural ganglia. 



39. A still more posterior section through the pleural centres. 



40. A transverse section through the proximal end of the subintestinal nerve, 



showing two bundles of nerve-fibres. 



41. Part of a longitudinal section through 'N. [Paranerita) gagates, $ , showing 



the relation of the spermatophore-sac [Sp.s.) to the gonadial division of 

 the coelom (g.co.) and the opening of the oviduco-calomic funnel {od.c.f.) 

 into the latter. 



Plate LVII. 



Fig. 42. A horizontal section through N. (Paranerita) gagates, $ , showing the 

 two divisions of the stomach, the extent of the lower part of the peri- 

 cardial ccelom, and the relations of the right auricle. 

 43. A similar section taken at a somewhat higher level, showing the extension 

 of the pericardial coelom towards the right side and the opening of the 

 reno-pericardial funnel into it. 



Plate LVIII. 



Fig. 44. A similar section, more dorsal than fig. 43, showing the relations of the 

 epididymis to the viscera. 



45. A section through the uropore, more highly magnified, showing the relations 



of the visceral ganglion and reno-pericardial canal. 



46. A section showing the opening of the reno-pericardial canal into the peri- 



cardial division of the coelom in A". {Paranerita) variegata and the 

 extension of the ciliated epithelium of the ureter {cile/p.) into the 

 bladder. 



Plate LIX. 



Fig. 47. A section through the ureter and adjacent part of the kidney in JV^. {Para- 

 nerita) variegata, showing the opening of the reno-pericardial canal into 

 the glandular part of the kidney and the ciliated passage (cil.p.) leading 

 directly from the latter into the ureter. 



48. A longitudinal section through the genital complex of X. {Paranerita) 



gagates, $ . 



49. Part of a horizontal section through AT. {Paranerita) variegata, showing 



the opening of the hypobranchial gland {Hy.g.a.) into the mantle-cavity. 



