M. Trecul on the Structure of the Leaves of Palms. 27 



in the Syllse and the other little Nereids which have been the 

 subject of my investigations, I have never perceived any peculiar 

 organ from which the light appeared to emanate. The muscles 

 alone, and particularly the muscles of the feet, have appeared to 

 me to present this phsenomenon. I have seen, moreover, some 

 SyllfB for instance shine through the whole extent of their bodies ; 

 and in this case the comparison to a thread of burning sulphur 

 is striking and just. This is the appearance to the naked eye ; 

 but under the magnifying glass this thread is divided into a 

 double range of luminous points corresponding to the feet. 



I am far from denying that certain animals may have organs 

 charged with secreting light, as certain fishes possess those for 

 secreting electricity ; but up to this time I have never seen that 

 sparkling light show itself except in the muscles and at the 

 moment of contraction. There may undoubtedly exist on this 

 point reasonable uncertainty with regard to those Annelids 

 whose foot-muscles are lodged in the abdomen ; but this cannot 

 be true with resjjcct to the Ophiura, and nothing is easier than 

 to prove this even to the iruaided vision, as in the latter the 

 phosphorescence appears along the arm, and only during move- 

 ment. Moreover, the details which will be given beyond of the 

 phosphorescence of the Noctilucce will show plainljr^ I believe, 

 that these animals have no special organ for producing the light. 



Finalljf, the Photocharis observed by Ehrenberg secreted a 

 liquid which left luminous traces on the objects which came in 

 contact mth it. This peculiarity I have also met with in one of 

 my Annelids ; but generally in the latter, and especially also in 

 the Ophiura, the light was owing entirely to the scintillations, 

 and disappeared with them. It is, however, easy to believe that 

 the modes of phosphorescence which we have admitted may co- 

 exist in the same animal. 



[To be continued.] 



VII. — On the Structure of the Leaves of Palms. 

 By M. A. Trecul*. 



NoTWiTHSTANDixa the important investigations of Von Mohl 

 and Mirbel, there still remains considerable uncertainty upon 

 the structure of the leaf in the Palms. For instance, what is the 

 ligula of the flabelliform leaves of many of these plants ? Are 

 their lobes the natural divisions of the leaf, or only accidental 

 vents of its substances ? Both these opinions are advanced. 

 How is the plaited limb of these leaves formed ? Are the pin- 



* From the Comptes Rendus, May 16, 1853, p. 857. 



