12 
Huxley on Lachiularia socialis. 
united free swimming colonies, resembling, in this state, the 
genus Conochilus. 
The process of development of these ova is therefore exactly 
that which takes place in all fecundated ova, and would lead 
one to suspect that spermatozoa should be found somewhere 
or other. 
Now, from the observations of Mr. Dalrymple, we should 
be led to seek a distinct male form with the ordinary sperma- 
tozoa. From those of KoUiker, on the other hand, we should 
equally expect to find each individual a hermaphrodite, with 
the very peculiar spermatozoon-like bodies which he has de- 
scribed in Megalotrocha. 
I must have examined some scores of individuals of Lacinu- 
laria 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 many individuals 
singular bodies, which answered precisely to Kolliker's descrip- 
tion of the " spermatozoa" Megalotrocha. They hadapyri- 
form head about 1-lOOOth in. in diam. (fig. 19), by which 
they were attached to the parietes of the body, and an append- 
age four times as long, which underwent the most extraordi- 
nary contortions, resembling however 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 append- 
age, which was zigzagged, while the other remained smooth. 
According to KoUiker 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 ?* Against this view we have 
* Leydig (loc. cit., p. 474) has observed, in several cases, what I de- 
scribe as probable spermatozoa, but considers them to be parasites. 
He does not notice the similarity of these bodies to those described by 
KoUiker in Megalotrocha ; but thinl^s that the l:.tter has been misled by 
the vibratile organs. 
Leydig does not appear to be acquainted with the important observa- 
tions of Dalrymple, Brightwick, and Gosse ; but brings forward as the 
true spermatozoon a terfium quid, 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 into the wheel-organ as into the caudal appendage. 
They are yellowish, globular bodies, with sharp contours, l-5000th to 
l-1700th of an inch in diameter, with a double centre and a lighter peri- 
phery. The surface is covered by a mesh-work of bands projecting in- 
