NOTES AND MEMORANDA. 



441 



Vignal is, on the contrary, convinced of tbe muscular nature of 

 the tentacle, " On the establishment and breaking of the current," he 

 says, "the flagellum (the tentacle of Eobin) contracts in its usual 

 manner ; the contraction is more rapid and energetic at the breaking 

 of the current. When I applied an induced current with rapid inter- 

 ruptions, the flagellmn became tetanically contracted, and continued 

 in this state for three or four minutes, then it gradually relaxed under 

 the influence of fatigue." There would therefore be, according to 

 Vignal, " analogy between the contractions of the tentacle, and those 

 presented by the muscles of animal life." However that may be, the 

 movements of the tentacle never lead the Noctiluca to change its 

 place ; they merely cause it, as Sm-iray has already shown, to oscillate 

 in its place. 



As for the phenomenon of phosphorescence, it is due, according to 

 Yignal, to a property of the protoplasmic mass, to the exclusion of 

 the other parts of the body. We know that the phosphorescence 

 attains its maximum by the agitation of the water ; according to Vignal, 

 this is an effect of which the cause is merely the mechanical iri'itation 

 of the Noctilucce : experiment has shown him that if oxygen intervenes 

 in the phenomenon, it is as a necessary agent to life, and not as an 

 oxidizer. Whilst studying the influence of heat on photogeny, he 

 observed that a temperature of 37^ (C.) augments the phosphorescence 

 and, above all, renders it more persistent, whilst a temperatiu-e of 39° 

 kills the Noctilucce almost immediately. Finally, Vigual maintains 

 that electricity suj)plied by a Grenet pile, or by an induction apparatus, 

 neither increases nor lessens the brilliancy of the light emitted, a 

 result contradictory to those formerly obtained by De Quatrefages, 

 Eobin, and Legros. 



In an analysis of the two papers by M. G. Carlet, from which we 

 take the above, he remarks that neither Eobin nor Vignal have 

 observed the existence of the anus admitted by Professor Huxley, and 

 it would seem, therefore, to be clear that the alimentary residues are 

 rejected by the oral aperture, the sole orifice of the body. Professor 

 Huxley also described in the Noctilucce permanent stomachs, which it 

 must be considered do not really exist — these are vacuoles in the 

 interior of the body, of variable number and volume, which are dis- 

 placed by the movements of the protoplasm; they contain diatoms 

 and other alimentary corpuscles, and represent only temporary 

 stomachs.* 



The dead bodies of Noctiluca miliaris left upon a beach in Beau- 

 maris Bay by the receding tide, are said to have been of an orange-red 

 colour. I 



Flagellum of Euglena viridis. — In a " Notice to Correspondents," 

 in ' Science-Gossip,' | the editor mentions that the flagellum of a 

 specimen of Euglena viridis sent to him terminated in a bulb. The 

 bulb was used occasionally as a kind of sucker against the glass sides 

 of the zoophyte trough. 



* ' Rev. lutcmat. Sci.,' iii. (1879) 47. 



t • Sci.-Goasip,' No. 173, p. 113. X I'jW., P- 11!>- 



