1836 British Association. 



amined the roots of these plants, and found that wherever the disease appeared in the 

 leaves there was evidence of disease in the roots. He believed the root was first at 

 fault. He quite agreed with Mr. Westwood in the necessity of a more general know- 

 ledge of Natural History. — SirW. Jardine said, that chemical investigations of a very 

 accurate nature, both of the soil and the potato, were being carried on in Edinburgh. 

 He had found that potatoes grown on moss soil were more free from disease than 

 others. This did not arise from the newness of the soil, for he had had some potatoes 

 entirely spoiled which were planted in an orchard recently turned up. He had seen 

 the stem and root very much affected without the leaves being diseased at all. — Mr. 

 Hogan called attention to a method he had pursued of preventing the disease in the 

 potato by growing them from seed. — Mr. C. Darwin had brought the seed of the po- 

 tato from Peru, and the tubers grown from it were quite as much affected as any other. 

 — Dr. Kelaart stated that he had recently heard from Ceylon that the potatoes had 

 been attacked in that island. — A Member said that he had just received letters from 

 New Zealand, and the potato was also affected there. — The Rev. N. Young, of New 

 College, exhibited some potato-leaves affected by the Aphis. 



Mr. Murray communicated a paper ' On the Vitality of Potato-Seeds,' in which 

 the seeds of the potato had remained fifteen years in the ground, and then when the 

 soil was turned up they vegetated and produced a crop. 



1 On the Structure of Nautilus Pompilius,' by Prof. Van der Hoven, of Leyden. 

 — My friend, De Vriese, lately gave me a specimen of Nautilus Pompilius, which was 

 in a bad state of preservation ; but still of great interest to me, as I found occasion to 

 observe a conformation of the head quite distinct from that which has been described 

 by Owen and Valenciennes. As to the external tentacula, I found only this very un- 

 important modification — that there were but nineteen at each side, instead of twenty. 

 Internal to this part, whose upper or dorsal part, called hood by Owen, fills entirely 

 the opening of the shell, the integument forms a prolongation, rising up to another 

 more internal circle. To the ventral or inferior side, this prolongation unites by a 

 transverse part with the external tentacular ring. This part shows many transverse 

 impressions parallel to the margin, and many irregular excavations, which give to it 

 a reticulated appearance. The prolongation is divided on each side into eight digita- 

 tions of different size, enclosing each a tentacle similar to that of the internal set, but 

 of a more minute size. Those parts correspond to the superior labial processes of 

 Owen (' Memoir on the Pearly Nautilus,' Tab. iv. g. g.) ; but in Owen's description, 

 and also in that specimen which has been described by Valenciennes, there are many 

 more tentacula — twelve in Owen's specimen, and thirteen in that of Valenciennes. 

 The last-named author calls this part the superior pair of the internal arms. Toward 

 the inferior part of the head, nearer to the infundibulum, which is situated at the me- 

 dian ventral line, there are two other processes in Owen's and Valenciennes' spe- 

 cimens: — the inferior labial processes of the former — the inferior pair of the internal 

 arms of the latter. Owen attributes, also, twelve tentacula to each of these processes. 

 In this point my specimen is entirely different. On the right side I found four ten- 

 tacula ; three on a common flat pedunculus ; the fourth and inferior on a separate di- 

 gitation. I also cannot agree with Owen in calling these inferior labial processes — 

 interior as they were in his specimen. In the specimen examined by me they were, 

 on the contrary, more interior than the superior labial processes. But at the left side 

 a still greater difference was to be observed. Instead of a labial process, there was a 

 great conoid body compressed from each side : at the basis of its measure, from the 



