51 



June 13th, 1837. 

 Richard Owen, Esq., in the Chair. 



The reading of Mr. Frederic Debell Bennett's paper upon Ma- 

 rine Noctilucce was resumed. 



Mr. Bennett's notes upon the phsenomena connected with the lu- 

 minous appearances so often exhibited by the ocean, made during a 

 voyage round the globe, agree in their essential details, and lead to 

 the same general inferences, as the observations of his brother, Mr. 

 George Bennett, published in the Society's Proceedings for Ja- 

 nuary 1837; the experiments in all instances, as recorded in the 

 present memoir, tending to show that where the condition of marine 

 phosphorescence obtains, organized bodies, secreting phosphoric light, 

 will be found in greater or less abundance distributed throughout 

 the ocean ; these bodies being sometimes so minute as not to be de- 

 tected by the naked eye, whilst at other times the luminosity api)ears 

 to originate in the presence of vast numbers of Pyrosomata and 

 MednscB, which latter, when removed from the water, retain, while 

 vitality lasts, their luminous properties, and are capable of commu- 

 nicating the phosphoric matter to objects with which they may be 

 brought in contact. An interesting fact noticed by the author is 

 that the Cleodora cuspidata, which is found floating in great numbers 

 on the surface of the sea in various parts of the Pacific Ocean, ex- 

 hibits a speck of delicate blue light, shining through the apex of its 

 extremely thin shell. 



In the following passage Mr. Bennett refers to a paper communi- 

 cated by him on a previous occasion, and published in the Society's 

 Proceedings. 



"On the night of the 1 1th of last October, when in lat. 4° S., long. 

 18° W.,I again witnessed the beautiful spectacle afforded by the pre- 

 sence in the sea of vast numbers of the Pyrosoma Atlanticum. Upon 

 this occasion their number must have been very great, since the ship, 

 proceeding at a rapid rate, continued during the entire night to pass 

 through distinct, but extensive fields of those molluscs, floating, and 

 glowing as they floated, on all sides of her course, and capable of be- 

 ing captured by net to almost any amount. Not far from the same spot 

 I first noticed these luminous molluscs, during a voyage to India ; and 

 an account of their eflFects in illuminating the ocean, accompanied by 

 some obtained specimens, I communicated in a paper to this Society, 

 published in No. 6 of the Proceedings. To that account I have to 

 add, from more recent observations, that since the Pyrosoma is en- 

 veloped by a firm membranous tunic, and the luminous power resides 

 in small brown particles abundantly imbedded in the parenchyma- 

 tous structure of the body, no luminous matter is communicated from 

 its surface to any fluid or solid in contact with it. But if the Py- 

 No.LIV. — Proceedings of tue Zoological Society. 



