230 Transactions of the Boyal Microscojoical Society. 
I found and captured it. When it was transferred to a com- 
pressorium and gently held captive, it proved to be a newly hatched 
specimen barely the yt-o c>f an inch long, and with so granular 
and corrugated a skin that I could not clearly make out the whole 
of its internal structure. Not indeed that there is ever much in a 
male to make out ; but it ought to have shown both the water 
vascular system and its muscles — and neither was to be seen owing 
to the unfavourable condition of the surface. The brain lying 
between the head and dorsal antenna was plainly visible, and so 
were the spermatic sac and penis — in the former of which could be 
seen the constant motion of the spermatozoa, though it was im- 
possible to make out the spermatozoa distinctly. 
As I did not see this animal hatched from one of the eggs of 
M. tyro, I cannot be certain that it is the male of that rotifer ; but 
there was no other rotifer in the trough except M. ringens of which 
it could be the male. 
I have however little doubt that it is the male of M, tyro, 
for I received soon afterwards from Mr. Wills, President of the 
Birmingham Microscopical Society, some excellent drawings of 
M. tyro, among which was figured a male animal very like the one 
I have just described, and which I. have drawn at Fig. 6. Mr. 
Wills had very kindly assisted me to find the pool from which the 
new rotifer had originally been taken, and on examining the speci- 
mens which he had taken home for himself had observed a male 
whirling round one of the females, and had secured a characteristic 
drawing of it. 
In both cases I believe M. ringens was also present ; — so that 
this male might belong either to M. ringens or M. tyro, but in 
either case it adds the genus Melicerta to the dioecious rotifers. 
It has been suggested to me that my new rotifer is possibly 
Tuhicolaria; and if this suggestion be correct a good many of 
my remarks at the commencement of this paper would lose their 
point. Now the genus Tuhicolaria was formed by Ehrenberg to 
receive a Melicertan that had no eyes at any time of its life, and 
lived in a gelatinous sheath. But I have seen the young female of 
M. tyro hatch from the egg, and have seen its two pink eyes when 
in the egg, and also when it has first escaped. Fig. 5 represents a 
very young one which I found just beginning to construct its 
sheath, and it too had two well-marked eyes : so that even if my 
rotifer is the same as that to which Ehrenberg gave the name 
of Tuhicolaria, it ought not, according to Ehrenberg's system, to 
be placed in a difi'erent genus from Melicerta ringens. It is true 
that Ehrenberg says he is not sure about the eyes, and he never had 
seen but two solitary specimens ; but without the distinction of its 
being eyeless there would remain only that of the gelatinous sheath, 
which is utterly insufficient to rest a new genus on. 
