Huxley on Lacinularia socialis. 
15 
inwards, at the line of demarcation of the two masses (fig. 23). 
The contents are precisely the same as before, viz., nuclei and 
elementary granules (fig. 24). This, indeed, may be seen 
through the shell without crushing the case. 
I was unable to trace the development of these ephippial 
ova any further. Those of Notommata, it appears, lasted for 
some months without change (Dalrymple). 
It is remarkable that in Lacinularia these bodies eventuallv, 
like the ephippium of Daphnia^ contain two ovum-like 
masses ; and there can, I think, be little doubt that the former, 
like the latter, are subservient to reproduction. 
There are then two kinds of reproductive bodies in Lacinu- 
laria : — 
1. Bodies which resemble true ova in their origin and 
subsequent development, and which possess only a single 
vitellary membrane. 
2. Bodies, half as large again as the foregoing, which re- 
semble the ephippium of Daphnia ; like it have altogether 
three investments ; and which do not resemble true ova either 
in their origin or subsequent development ; which therefore 
probably do not require fecundation, and are thence to be 
considered as a mode of asexual reproduction.* 
General Relations of the Rotifera. — It is one of the great 
blessings and rewards of the study of nature that a minute and 
laborious investigation of any one form tends to throw a light 
upon the structure of whole classes of beings. It supplies us 
with a fulcrum whence the whole zoological universe may be 
moved. I would illustrate this truth by showing how, in my 
belief, the structure of Lacinularia^ as thus set forth, taken in 
conjunction with some other facts, gives us a clue to the solu- 
tion of the questio vexata of the zoological position of the 
Rotifera, and thence to the serial affinities of a large portion of 
the Invertebrata. 
* Leydig distinguishes particularly between the ordinary, and what I 
have termed, the ephippial ova. 
His description of the latter agrees essentially with that which has been 
given above ; but he has not, I think, observed the genesis of the ephippial 
ova with sufficient care, and he thence interprets their structure by sup- 
posing that they are ordinarily fecundated ova, which have undergone 
a peculiar method of cleavage. The tendency of the observations de- 
tailed above, on the other hand, is to show that they are not ova at all in 
the proper sense, but peculiar buds like those of A'pliis or Oyrodactylus, 
and as such are capable of development without fecundation. 
In the new edition of Pritchard's ' Infusoria,' it is stated (p. 620), that 
*' in a recent paper by Mr. Howard on this species, he states that there 
are two kinds of reproductive bodies — one the ordinary ova, the other twice 
their size, representing gemmse." No reference is given to Mr. Howard's 
paper, and I have been at a loss to discover it, though desirous to do justice 
to him if possible. 
