STL 
TRANSACTIONS 
MICROSCOPICAL SOCIETY 
OF 
LONDON. 
Lacinularia socialis. a Contribution to the Anatomy and 
Physiology of the Rotifera. By T. H. Huxley, Esq., 
F.R.S., Assist.-Surgeon R.N. (Read Dec. 31, 185 J.) 
The leaves of the CeratopJiyllum^ which abounds in the river 
Medwaj, a little above Farleigh Bridge, are beset with small 
transparent, gelatinous-looking, globular bodies, about l-5th 
of an inch in diameter. These are aggregations of a very 
singular and beautiful Rotifer, the Lacinularia socialis of 
Ehrenberg. On account of their relatively large size, their 
transparency, and their fixity, they present especial advantages 
for microscopic observation ; and I therefore gladly availed 
myself of a short stay in that part of the country to inquire 
somewhat minutely into their structure, in the hope of being 
able to throw some light on the many doubtful or disputed 
points of the organization of the class to which they belong. 
We are told by Ehrenberg (' Infusions-Thierchen,' p. 403) 
that Lacinularia socialis was discovered and described 
anonymously in Berlin in 1753. Miiller bestowed upon it 
the name of Vorticella socialis, which was changed by 
Schweigger to Lacinularia in 1820. Previously to the time 
of Ehrenberg the genus appears to have become confounded 
with Megalotrocha ; and indeed Dujardin very reasonably, 
as it seems, altogether denies the propriety of their separa- 
tion. The extreme resemblance of the two forms is admitted 
by Ehrenberg himself ; but he considers the attachment of 
the ova of Megalotrocha by a filament to the body — a circum- 
stance which does not obtain in Lacinularia — diVidi the exist- 
ence of a gelatinous investment in the latter which is not 
found in the former, to be sufficient grounds of distinction. 
The matter is not one of much importance, but I call 
attention to the close alliance between Megalotrocha and 
Lacinularia for a reason which will appear in the sequel. 
The globular aggregations of which I have spoken are not 
VOL. I. b 
