new and rare British Copepoda. 361 
thorax there is on each side a deep lateral sinus, and the 
body is furnished on each side with four large elongate tooth- 
like processes that overlap each other on the ventral aspect ; 
the abdomen is short and narrow, two-jointed; the terminal 
joint, which is about three times the length of the first, has 
the end somewhat trilobed and is furnished with three very 
small terminal hairs. Ovisacs large, broadly oblong, diver- 
gent, each ovisac extending laterally beyond the body of the 
animal. 
Habitat. Parasitic on the nudibranch molluse Lomanotus 
Genei, Ver., obtained at a depth of 8 fathoms in Valentia 
Harbour, Ireland. 
Remarks. In this remarkable parasite there is no apparent 
segmentation of the body, and the head is distinguished from 
the body only by the lateral sinuses already described ; on 
the other hand, the abdomen is distinctly jointed, and consists 
of two segments, as shown in the drawing. The parasite 
was entirely buried in the body of the molluse with the 
exception of the last abdominal segment and the ovisacs. 
Figure 2 represents the mollusc with the parasite én situ. 
No antennules, antenne, or mouth-organs could be observed. 
The parasite was slightly injured during its removal from 
the body of the mollusk, and the appendages on one side 
somewhat displaced; but the drawing shows them in what 
we believe to be their natural position. We have been 
unable to identity this parasite with any described genus or 
species. 
Additional Note.—In the ‘ Journal of the Marine Biolo- 
gical Association,’ vol. i., n. s., p. 426, Mr. Garstang, in an 
article on rE be ‘Opisthobranchiate Mollusca of Plymouth,” 
refers to ‘¢a remarkable parasitic Copepod ” which he had 
observed on a specimen of Lomanotus Genet, and which he at 
first supposed to be the eggs of the molluse ; probably this 
parasite may be similar to “the form now described. 
EXPLANATION OF THE PLATES. 
PLATE XV. 
Stenhelia Blanchardi, sp. n. 
Fig. 1. Female, seen from the side, x 53. 2. aa x 126. 
3. Antenna, X 168, 4. Mandible, x 190. 5. _ Anterior foot- 
jaw, Xx 380. 6. Posterior foot-jaw, x 380. Foot of first 
pair of swimming-feet, x 190. 8. Foot of found pair, x 126. 
9. Foot of fifth pair, x 168. 10. Abdomen and caudal stylets, 
x 80. 
