Miscellaneous, 63 



The form of the eyes of caterpillars, and their position at the root 

 of the mandibles, appear to be perfectly appropriate to the mode of 

 life of these animals. The prehension and assimilation of food con- 

 stitute the essential phenomena of their life. The exercise of sight 

 is limited to the immediate perception of nutritive materials. The 

 distance from the point of the mandibles to the ocelli being therefore 

 the measure of average vision, this distance must be exceptionally 

 short. The laws of optics necessitate in this case an extremely strong 

 curvature of the crystalline ; and this curvature is realized in all 

 caterpillars. The office of the iris is no doubt to contract under the 

 influence of too intense a light ; for this organ is endowed with an 

 extreme contractility. Lastly, the enveloping bodies, the muscular 

 layer, and the enveloping membranes are very strongly pigmented, so 

 as to concentrate the light upon the nervous elements. — Siebold 

 undKdlliker's Zeitschrift, Bd. xvi. p. 27 ; Bihl. Univ. Nov. 25, 1866, 

 Bull. Sci. pp. 272-275. 



Deep-Sea Life in the Ocean. 



In my Report to the British Association, at their last meeting, on 

 dredging among the Hebrides, I quoted a paper by Professor Lovea 

 on the results of the Swedish expedition to Spitzbergen in 1861 

 under Dr. Otto Thorell. A translation of that paper was sent to me 

 by a friend from Copenhagen, and I had no opportunity of comparing 

 it with the original. Professor Loven has now pointed out to me a 

 mistake in the translation, which, in justice to him, I hasten to 

 correct. Instead of his saying that, from 60 to 80 fathoms down to 

 the greatest depth known to be inhabited by animals, the bottom is 

 '* everywhere" covered with a soft and fine mud or clay, it should 

 be "wherever" the bottom is so covered. This substitution of one 

 word for another makes all the difference. The learned author was 

 well aware of the existence of rocky ground, even at very great 

 depths. I beg to offer my sincere apology to him for having thus 

 misrepresented his views. 



J. GwYN Jeffreys. 



25 Devonshire Place, Portland Place, 

 1st Dec, 1866. 



Researches on the Geryonidae. By Professor Hackel. 



Among the Craspedote Medusee the family of the Geryonidse is 

 distinguished by the length of the stomachal peduncle, which causes 

 these animals to resemble umbrellas furnished with long handles. 

 This character certainly occurs also throughout the family Geryo- 

 uopsidse established by Agassiz, and in some Oceanidse and Thau- 

 man tiadse. But the Geryonidse are distinguished from these families 

 by the peculiar form of their generative organs, which extend like 

 delicate leaves in the subumbrella, without projecting into the cavity 

 of the umbrella. Gegeubaur, indeed, ascribes to the Geryonidse 

 another important character connected with the gastrovascular sys- 



