i895. NOTES AND COMMENTS. 85 



metameric character of the organs in Nautilus. Willey had already 

 shown, in the paper referred to above, that the post-anal papilla 

 represented the two posterior osphradia, or sensory organs at the 

 base of the two hinder gills. Mr. Kerr suggested that the nerve- 

 branches to this papilla represented the supra-anal commissure of the 

 Amphineura. He supposed that the genital ducts of the female were 

 homologous with the viscero-pericardial pores, so that there would be 

 two pair of openings from the viscero-pericardial chamber to the 

 exterior, just as there are two pair of renal openings. There is, 

 however, nothing gained by homologising the viscero-pericardial 

 pores with nephridia, for surely their position and opening into the 

 nephridia in other molluscs is not so primitive as their direct opening 

 to the exterior in Nautilus. It is recognised that the generative 

 ducts are paired right and left, but that the left duct is rudimentary. 

 It is therefore probable that, as Mr. Kerr suggested, the penis is a 

 paired structure derived from the outer skin, with the left half 

 rudimentary and having lost its connection with the duct. 



It is generally held that the arms of the Cephalopoda are 

 processes of the fore-part of the foot that have grown up round the 

 head, and this view is based on the facts of development and on the 

 circumstance that the arms receive their nerve-supply from the pedal 

 ganglion or from a small ganglion connected therewith. Mr. Kerr 

 apparently did not think any of the evidence worth discussing except 

 that relating to the nerve-supply, and here he boldly denied that the 

 pedal ganglion was the pedal ganglion, in other words, that it was 

 homologous with the ganglia in the foot of gastropods. He believes 

 that the ganglia of gastropods and cephalopods have been indepen- 

 dently derived from a condition of continuous nerve-strands, such as 

 occurs in Chiton. This is most probable, but it does not prevent the 

 ganglion in question having been a pedal ganglion in the early days 

 of its development. Mr. Kerr's conclusion is that " the Amphineura, 

 and especially the Chitons, are of all living Mollusca those which 

 most nearly approximate to the ancestral form of the time when the 

 cephalopods diverged from the main molluscan stem." In the con- 

 dition of the nephridia, however. Nautilus is even more metameric 

 than Chiton, and it is surely possible that the various organs may 

 have been affected by metamerism independently in those Cephalo- 

 poda that took to coiling their shells, while remaining simple in tliose 

 whose shells remained straight and eventually became enveloped by 

 the mantle. We look forward with considerable interest to the 

 publication of the complete paper. 



The Cultivated Cineraria. 



It is a pretty quarrel, conducted with an agreeable virulence ; 

 and the beginning and the end leave us where we were. This was the 

 fashion of it. Professor Weldon introduced a discussion on variation 



