Huxley on Lacinularia socialis. 
13 
the unquestionable separation of the sexes in Notommata^ 
and the very great difference between these and the spermato- 
zoa of Notommata. Neither are the mode of development nor 
the changes undergone bj the ovum any certain test that it 
requires or has suffered fecundation, inasmuch as the process 
closely resembles the original development of the aphides {see 
Ley dig, Siebold and Kolliker, Zeitschrift, 1850). 
In the view that Kolliker's bodies are true spermatozoa, it 
might be said — 1. That the sexes are united in most Disto- 
mata, for instance, and separated in species closely allied (e.^. 
D. Okenii). 
2. That the differences between these bodies and the sperma- 
tozoa of Notommata is not greater than the difference between 
those of Triton and those of Rana. 
3. That their development from nucleated cells within the 
body of Megalotrocha (teste Kolliker) is strong evidence as to 
their having some function to perform ; and it is difficult to 
imagine what that can be if it be not that of spermatozoa. How- 
ever, it seems to me impossible to come to any definite con- 
clusion upon the subject at present.* 
Kolliker supposes that Ehrenberg has seen the " spermato- 
zoa " and has taken them for the " long vibratile bodies while 
Siebold imagines that Kolliker has taken the long vibrating bodies 
for spermatozoa. No one, however, who has seen both struc- 
tures can be in any danger of confounding the one with the other. 
Asexual propagation of Lacinularia. — Whatever may be the 
nature of the process of reproduction just described, there exists 
another among the Rotifera, which has been noticed by almost 
every one, but not hitherto distinguished or understood. This 
is the production of the so-called " winter ova," but which from 
their analogy with what occurs in Daphnia^ I prefer to call 
" ephippial ova." 
Ehrenberg says that many ova of Hydatina have a double 
shell, and between the two shells there is a wide space. 
" Similar ones occur in many Rotifera, in various often irre- 
gular forms : these have a much slower development, and I call 
them thence winter ova " (p. 413). See also his account of 
Brachionus urceolaris (p. 512). He does not notice the occur- 
rence of these ova in Lacinularia or Megalotrocha, 
ternally, which give the body a mosaic (parquettirtes) appearance. Im- 
moveable hairs, l-1700th of an inch long, may be seen in isolated globules 
to radiate from the surface." 
I have not observed any of these bodies. 
* I may mention here that I have found in Melicerta an oval sac lying 
below the ovary, and containing a number of strongly-refracting particles 
closely resembling in size and form the heads of the spermatozoa of Laci- 
nularia. 
