264 NOTE uroN the occurrence of 



Royal Academy of Sciences of Brussels (vol. vi., No. 4). A 

 translation of his paper, without, however, any figures, is in the 

 " Annals of Natural History" (vol. vi., p. 344). The original 

 of this I have not seen. Professor Meyer he states to have 

 previously discovered these structures, but his account of them 

 would appear to be insufficient. In addition to the observations 

 briefly detailed by Professor Morren, I have little to say ; it is 

 chiefly for the sake of recording, in lithograph, some of the 

 commoner forms assumed by these organs— for their principal 

 interest would seem to rest in their morphological relations — 

 that I consider them worthy of present notice. 



The rotiferon inhabiting the cysts observed by me was deter- 

 mined by P. H. Gosse to be, I believe, the common Rotifer 

 vulgaris. The same gentleman also kindly referred me to the 

 paper above alluded to. Upon the whole, I can quite confirm 

 Professor Morren's statements. He observed, however, some 

 " greenish tubes" appended to the free extremities of his cysts, 

 which I did not, after a close examination of numerous exam- 

 ples, succeed in finding. I am ready to think that these may 

 most probably have been due to foreign adhering filaments of 

 some Alga. The problem involved in the presence of these 

 animals in the interior of the Vaucheria does not present any 

 difficulty, inasmuch as upon the rupture of one of its filaments, 

 either by freeing a spore, or from some other cause, the width 

 of its tube is abundantly large to admit the Rotifer ; and, pro- 

 vided the transverse septum be not formed over the exposed end 

 of the contents, nothing would obstruct its traversing the fila- 

 ment until reaching some one of the lateral " booklets," or 

 " hornlets" (h'drnchen), normally provided for the segregation 

 of spores and antherozoids. One of these, unaltered by the 

 intruding animalcule, is shown by Fig. 7. It is clear that once 

 fairly established in the plant, by their oviparous multiplication, 

 a mass of the Alga may soon become quite colonised. The 

 various forms assumed by these appendages, represented on the 

 accompanying Plate, I conceive to be due, perhaps always, to 

 the development, more or less diverted from its ordinary course, 



