LACINULARIA SOCIALIS I 37 



each individual a hermaphrodite, with the very peculiar spermatozoon- 

 like bodies which he has described in Megalotrocha. 



I must have examined some scores of individuals of Lacinularia 

 with reference to the former case, without ever finding a trace of a 

 male individual. All were similar, all contained either ova or ovarium, 

 nowhere was an ordinary spermatozoon to be seen. On the other 

 hand, I found in man}- individuals singular bodies, which answered 

 precisely to KoUiker's description of the " spermatozoa " of Megalo- 

 trocha. They had a pyriform head about i-ioooth in. in diam. 

 (fig. 19), by which they were attached to the parietes of the body, and 

 an appendage four times as long, which underwent the most extraor- 

 dinary contortions, resembling, ho«'ever, a vibrating membrane much 

 more than the tail of a spermatozoon ; as the undulating motion 

 appeared to take place in only one side of the appendage, which was 

 zigzagged, while the other remained smooth. 



According to Kolliker again, these bodies are found only in those 

 animals which possess ova undergoing the process of yolk division, 

 while I found them as frequently in those young forms which had not 

 yet developed ova, but only possessed an ovary. 



Are these bodies spermatozoa P'- Against this view A\'e have the 

 unquestionable separation of the sexes in Notommata, and the very 

 great difference between these and the spermatozoa of Notommata. 

 Neither are the mode of development nor the changes undergone 

 by the ovum any certain test that it requires or has suffered fecunda- 

 tion, inasmuch as the process closely resembles the original develop- 

 ment of the aphides {see Leydig, Siebold and Kolliker, Zeitschrift, 

 1850). 



In the view that KoUiker's bodies are true spermatozoa, it might 



^ Leydig (loc. cit. p. 474) has observed, in several cases, what I describe as probable 

 spermatozoa, but considers them to be parasites. 



He does not notice the similarity of these bodies to those described by Kolliker in 

 Megalotrocha ; but thinks that the latter has been misled by the vibratile organs. 



Leydig does not appear to be acquainted with the important observations of Dalrymple, 

 Brightwick, and Gosse ; but brings forward as the true spermatozoon, a tertimii qiad, 

 whose description I subjoin in his own words : — " In almost every colony we meet with 

 from one to four (in large colonies) individuals which are distinguishable from the rest at the 

 first glance. By reflected light they appear quite white, which appearance arises from 

 peculiar corpuscles which. fill the cavity of the body more or less completely, and are 

 driven hither and thither by the contractions of the animal, as well as into the wheel-organ 

 as into the caudal appendage. They are yellowish globular bodies, with sharp contours, 

 l-5oooth to i-i70oth of an inch in diameter, with a double centre and a lighter periphery. 

 The surface is covered by a mesh-worlc of bands projecting internally, which give the body 

 a mosaic (parquettirtes) appearance. Immovable hairs, i-iyooth of an anch long, may be 

 seen in isolated globules to radiate from the surface.'' 



I have not observed any of these bodies. 



