180 M. de Quatrefages on the Phosphorescence of 



I have received the May number of the ' Annals of the Lyceum 

 of New York ' (vi. 35), containing a figure and description of the 

 animal of Rotella made by the Rev. S. B. Fairbank of Bombay, 

 and transmitted by him to the late Professor C. B. Adams. 



Mr. Fairbank describes the lobe on the right side of the 

 body, which is an extension of the front end of the lateral fringe, 

 as a lobe probably " of the mantle which partly clings to the 

 shell, but does not at all envelope it ;" and he calls the veQ " a 

 siphon,^' and describes it " as a tube, the side being slit next 

 the outer lip of the shell and filled with cilia ; the cilia are tipped 

 with black ; sometimes they gather against the sides, so that you 

 see the tube with a black rim, but usually they are disposed 

 much as I have dotted them in the figure,^' that is to say, like 

 the rays of a star. The lateral fringe, so constant in all the 

 Trochidce, is entirely overlooked in this figure and description. 

 He observes that these shells are found where the water would 

 leave them dry at least two hours each tide, just buried in the sand; 

 when placed in water, they did not move about much, but only 

 raised their siphons. As represented in the figure, the " siphon " 

 greatly resembles the fringed siphonal tube of a bivalve shell ; but 

 I can scarcely conceive that the veil, as I observed it in the animal 

 in spirit, could form such a complete tube. The part here called 

 a siphon can only be considered as a great development of one 

 of the fringed lobes which are found near the base of the ten- 

 tacles of most Trochidce and TurbonidcB, and which is a continu- 

 ation over the head of the lateral membranes of these animals. 

 It dififers chiefly from the other Trochida in the rostrum not 

 being developed, and the mouth consisting of a round opening 

 under the base of the veil, and in the peculiar development of 

 the frontal appendages. 



XXI. — On the Phosphorescence of some Marine Invertebrata. 

 By M. A. De Quatrefages*. 



[Concluded from p. 27.] 



Second Part. — General Observations on Phosphorescence, 



1. Description of the Phenomenon. — It would be useless to 

 repeat here all the details given by travellers; I will confine 

 myself to some remarks on my own observations. 



The phosphorescence of the sea has appeared to me under two 

 different forms : — 1st, a result of scintillations more or less nu- 



* From the Annales des Sciences Naturelles, vol. liv. 3rd series, as in- 

 serted in Silliman's American Journal of Science for July, 1853. 



