148 
BRITISH ENTOMOSTRACA. 
They are curved upwards and backwards, and are always 
contained within the shell, never being extended. Their use, 
according to Straus, is to support the ovaries.* The pos- 
terior portion of the body or abdomen (t. XVIII, f. 1 i) 
is conical-shaped, terminating in two lengthened stalks, 
each of which gives off at the extremity two short hooks, 
with a third implanted on the upper edge, a little above 
them. This abdominal portion of the body is unattached, 
and possesses much freedom of motion, the animal ex- 
truding it from the shell at pleasure. One great use of 
it seems to be to clean the interior part of the shell, which 
its length and mobility fit it well for ; but Straus asserts 
that the object of this organ is for depositing the eggs. 
The anatomy of the internal parts of the body is more 
difficult to make out distinctly. 
The alimentary canal, according to Straus, consists of 
a short, narrow oesophagus, a large oblong stomach, occu- 
pying the whole of the dorsal region of the body, and a 
simple intestine nearly as large as the stomach, becoming 
narrower towards the posterior extremity, and opening 
by an anus between the two stylets which form the tail. 
The ovaries are two large, simple, conical vessels, placed 
externally upon the posterior portion of the body, and 
open one at the side of the other into the anterior part of the 
extremity of the abdomen, where they communicate with 
the canal formed by the tail or abdomen. There is another 
organ, the use of which is not so well ascertained. It is 
a large and conical mass, situate above the articulation of 
the mandibles, of a granulated structure apparently, and 
of a light colour. Straus says, that as he could not see 
exactly its termination, he is ignorant of its use, but sup- 
poses that it must be either the salivary glands, or the 
testicle. 
The heart and nervous system have as yet escaped 
observation. The animals of this family are all inhabitants 
* Jurine considers them as somewhat connected with the matrix, but 
says he is ignorant of their use. The figure which he gives of them is very 
incorrect. 
