i894. NOTES AND COMMENTS. 89 



Another possible explanation of apparent tropical conditions is 

 suggested by Dr. V. Ball in a paper on the folk-lore of the volcanoes 

 and hot springs of India, published in the Proceedings of the Royal Irisli 

 Academy (ser. 3, vol. iii., pp. 151-169). No one who has travelled in 

 volcanic districts, where hot springs are still active, can have failed to 

 observe that they have considerable influence on the surrounding 

 vegetation, and even, as has been pointed out by various writers, on 

 the fauna, both aquatic and terrestrial. It is not only the lower 

 animals, but also human beings, who, like the Maoris and the 

 Japanese, flourish in the neighbourhood of hot springs where the 

 purely climatic conditions would otherwise be too severe. Dr. Ball, 

 then, writes as follows : 



" Where the fossils of animals or plants are found which seem to 

 indicate tropical or semi-tropical conditions of the climate at the time 

 when they lived, may it not be possible to suggest, especially if there 

 be any facts tending to prove the existence of different climatic 

 conditions elsewhere at the same time, that there may have been 

 widespread fumaroles or hot springs sufficient to have produced local 

 hot-houses in which animals and plants may have flourished, which 

 could not otherwise have existed in the normal conditions of climate 

 belonging properly to the time and place ? " 



Under certain circumstances the explanation might be plausible ; 

 but we doubt whether such circumstances have as yet presented 

 themselves to geologists. It must be remembered that such effects 

 would be extremely local, and that thermal activity would probably 

 leave other traces of its former existence in the shape of chemical 

 deposits. 



In the funnel of certain Cephalopods, several authors have 

 noticed a peculiar cushion-like organ, situated a little behind the 

 valve, and this has, for very insufficient reasons, been called " Verrill's 

 organ " by Hoyle and others. Its function and homology have been 

 the subject of some discussion. Ferussac and d'Orbigny confused it 

 with a transverse muscle ; H. Miiller, in 1852, thought it was a 

 stinging organ ; Verrill, in 1882, considered it " the true homologue 

 of the foot of gastropods"; Laurie, in i888, from rather insufficient 

 material, showed its glandular nature, and believed that it secreted 

 mucus, but his observations were criticised by Brock ; Hoyle, in 

 1889, believed that it served to close the funnel. That it is really a 

 mucous gland is now proved by the careful observations of G. Jatta 

 {Boll. Soc. Nat. in Napoli, vol. vii., p. 45, 1893), who has observed it in 

 32 species belonging to 21 genera, thus bringing the number of genera 

 in which it has been found from 10 to 27. He describes and figures 

 six main modifications of its arrangement, and gives excellent draw- 

 ings to show its microscopic structure in different stages of its 

 development. He concludes that this funnel organ is a mucous 

 gland homologous with the pedal glands of other moUusca. If this 



