THE ADHESIVE TENTACLES OF NAUTILUS. 207 



The Adhesive Tentacles of Nautilus, with some 

 Notes on its Pericardium and Spermatophores. 



By 

 Arthur Willcy, D.Sc. 



With Plate 11, 



Adhesive Tentacles. — In the plate (PI. 11) accompanying 

 this note I have given a sketch (fig. 1) taken from a living 

 nautilus showing the way in which the ordinary tentacles 

 are applied to a foreign object lying in the water (in this case 

 a glass vessel) so as to adhere very firmly to it ; whilst the 

 pre-orbital and post-orbital tentacles have no such adhesive 

 power, and remain erect on either side of the ocular bulb. As 

 I mentioned in a previous note, the ordinary tentacles some- 

 times adhere so tightly to a foreign body as to become torn 

 away from the animal when the foreign body is forcibly re- 

 moved. 



Spermatophore. — In Plate 11, fig. 3, is given a figure of 

 Nautilus porapilius, showing the spermatophore sac in 

 situ at the dorsal base of the buccal cone. This position 

 was originally discovered by Van der Hoevea; but it has not 

 been seen since, or at least not described, and Van der Hoeven's 

 figures are a little wanting in clearness. 



Pericardium. — The structure of the vena cava of 

 Nautilus, discovered by Owen, was again very exactly 

 described and figured by Keferstein in 1865. This was ap- 

 parently overlooked by Mr. Kerr in his work " On some 

 Points in the Anatomy of Nautilus pompilius^' (' Proc. 



VOL. 40, PART 2. NEW SEE. Q 



