449 
Floscularia pelagica , &c. By G. F. Bousselet. 
This, the smallest of the known species of (Ecistes, was found 
by Mr. John Hood in 1889 in various lakes in Scotland ; it appears 
to be widely distributed but not very abundant. The corona is oval 
and quite as large in diameter as that of (Ecistes muscicola or 
socialis, but the dorsal gap appears to be absent. 
The tube is built singly on stems and leaves of Kanunculus 
and Myriophyllum and is like that of (E . crystallinus in appearance. 
The internal organs are normal, but the characters enumerated 
above distinguish it sufficiently from all other species of (Ecistes. 
Size 1/120 to 1/105 in. Habitat: lakes in Scotland and 
Ireland. 
Asplanchna priodonta Gosse. 
This, abundant and widely distributed species has been so often 
studied that it seems difficult to find anything new in its organization. 
Yet by the application of staining agents I have discovered that the 
body-cavity of [this rotifer is divided into two distinct compartments 
by a very thin membranous septum, running from the head to the 
posterior part of the body, in a plane at right angles with a dorso- 
ventral one, and in such a way that the body -cavity becomes divided 
into a larger ventral and smaller dorsal compartment. 
In the living animal, towards the dorsal side of the body, four 
threads are easily seen, running from side to side, across the body-cavity, 
markedly parallel to each other, like ruled lines. The septum appears 
stretched on these threads, but is so thin and so hyaline that it 
cannot be seen by ordinary means, and appears so far to have been 
overlooked. 
The dorsal compartment contains no organs except the nervous 
threads of the dorsal antennae, which pass through it, and two other, 
either nervous or muscular, threads, fastened to the integument a 
little below the antennae. The ventral compartment contains the 
stomach and all the other organs. 
The staining in toto of well-preserved rotifers by selective stains 
promises to produce very important results, and certainly will greatly 
facilitate the study of these animals, as ( by this means obscure and 
unsuspected details may often he made very prominent. 
