238 
BRITISH ENTOMOSTRACA. 
Only one species has as yet been observed, which Mr. 
Allman has described at length in the ‘ Annals and Maga- 
zine of Natural History’ for July 1847. It is found 
swimming freely in the branchial sac of the Ascidia com- 
munis, and has been collected in various parts of Ireland. 
It was first publicly noticed by Mr. Paterson of Belfast, 
who briefly mentioned it at the meeting of the British 
Association in 1843. The species has been named by 
Allman — 
1. Notodelphys ascidicola. Tab. XXX, figs. 7, 8. 
Allman, Ann. Mag. Nat. Hist., xx, 1-9, t. 1, 2, f. 1-22. 
The cephalo-thoracic segment is prolonged anteriorly 
into a kind of beak, which is not moveable. Attached to 
this segment we find the eye, two pairs of antennae, the 
organs of the mouth, and one pair of natatory feet. 
The eye is situated, as in the Cyclopidae, in the centre 
of the superior and anterior portion of this segment. It 
is tolerably large, and is single. 
The superior antennae consist of about twelve short 
articulations, each provided with one or more setae. The 
inferior antennae (f. 7 a) are not branched, and are formed 
of four joints, the last of which is in shape of a curved 
prehensile claw. 
The labrum is well developed, and the mandibles (f. 7 b ) 
are strong organs, furnished with several stout teeth on 
their cutting edge. 
The first pair of foot-jaws (f. 7 c) consists each of a flattened 
peduncle and two branches ; one having six, the other 
three articulations, and bearing several long, stout, and 
finely plumose setae. The second pair of foot-jaws (f. 7 d) is 
very similar to the first, but their two branches have fewer 
joints ; one having three, and the other only one, but both 
terminated by plumose setae. The third pair (f. 7 e ) is 
composed of five articulations, the basal being very large, 
and the succeeding small, and furnished with stiff, not 
plumose setae. The fourth pair (f. 7 /) is smaller, formed 
