210 
MICROSCOPICAL SECTION. 
February 17th, 1862. 
Professor Williamson, F.R.S., President of the Section, 
in the Chair. 
Soundings ■were acknowledged from Captain W. B. Hall, 
of the P. and O. S. S. “ Tagus ,” taken off Ushant, Coast of 
France, and from Captain J. R. Husband, ship “ Florence 
Nightingale ,” taken off the Coasts of Patagonia and Tierra 
del F uego. 
Professor Williamson called the attention of the section 
to the new rotifer (Cephalosiphon Limnias), recently dis- 
covered by Mr. H. J. Slack, in a pond at Hampstead, and an 
account of which appeared in No. 1 of the Intellectual 
Observer of the present month. Attention was specially 
directed to the fact, that the animal only possesses one of 
those organs that have been designated “respiratory tubes,” 
“calcars,” and “ tactile organs ;” whereas, the Floscularian 
Rotifera, when furnished with them, have two. It remains 
to be ascertained from a study of the embryo, whether this is 
the typical condition in the Cephalosiphon, or whether there 
were primarily two, the missing one having been suppressed 
during the development of the embryo, as sometimes occurs 
amongst higher animals. 
The Secretary read a Paper, by Mr. Thomas Davies of 
Warrington, on Crystallisation. 
Mr. Davies treats more particularly upon some of the 
double salts, which show beautiful combinations of form and 
