686 ANATOMY oiT NAUTILUS POMPiLius. [June 18. 



to abandon it for the inherently much more probable view that 

 these structures are processes o£ the head region. 



15. Nautilus shows many strong resemblances to the Amphi- 

 neura, and it is probably amongst these latter that we have to look 

 for the nearest allies of the Cephalopoda. 



EXPLANATION OF THE PLATES. 



platk xxxvni. 



Fig. 1, Side view of an animal oi Nautilus pompilius, extracted from the shell. 



The funnel has been opened out and the mantle-flap partly cut away 



so as to give a better view of the various parts. 



h, hood ; t, tentacles ; e, eye ; / funnel separated by a deep groove 



from the hood-tentacle mass ; m, cut edge of mantle-flap ; g, gill ; 



s, siphuncle. 

 Fig. 2. Longitudinal section through the animal oi Nautilus very slightly to the 



right of the middle line. 



b, buccal cavity ; r, radula ; eg, supra-oesophageal nerve-cord ; pl.g., 

 posterior sub-oesophageal nerve-cord ; p.g., anterior ditto ; /, funnel 

 with its valve ; ph, crop with at gi.:. its opening into the gizzard ; 

 int., intestine ; an, anus ; k, kidney-chamber with follicular append- 

 ages of advehent vein projecting into it; p.foll., pericardial gland- 

 follicles projecting into pericardium ; v.c, vena cava. 



Plate XXXTX. 



Fig. 1. View of penis and sac of Needham from posterior (ventral) aspect. 



The outer wall has been removed so as to show a and h — the right 

 and left halves of the penis. 



c, sac of Needham ; d, corresponding structure of left side ; c, bristle 

 passing through opening of vas deferens into sac of Needham. 



Fig. 2, Spermatophore-receiving apparatus of an adult female with spermato- 

 phore (s) in situ. In this specimen the laminse of the organ were 

 continuous across the middle line. 



Fig. 3. The same organ in its more usual (paired) form. 



V NOV 1393 



