236 PHRYXUS HIPPOLYTES. 
terminal segment is minute, and unfurnished with ap- 
pendages. In Rathke’s dorsal figure of the species this 
segment is represented as bifid, but in the ventral one as 
entire, as appears also to be the case in our individuals. 
We have no hesitation in regarding our specimens as 
identical with Bopyrus abdominalis, elaborately figured in 
all its details by Kroyer in 1840, which is represented by 
him as attached to the under surface of the pereion of a 
species of Prawn. 
The young of this animal is oval and very convex, with 
very slight indications of articulations ; the head is large, 
with two dark round spots indicating the eyes; the upper 
antenne are short and apparently exarticulate, whilst the 
lower pair of antennz are about half the length of the 
body and six-jointed, with a pencil of terminal hairs. 
The body is furnished beneath with six pairs of strong 
subcheliferous legs, and the hinder part of the body, re- 
presenting the tail, is provided with five pairs of flattened 
elongate-ovate plates, strongly ciliated at their extremi- 
ties, the small obtusely triangular terminal segment being, 
moreover, furnished on each side with a larger curved 
lobe, bisetigerous at its tip. 
This species was first detected by Herr Rathke asa 
parasite beneath the shell of a species of Hippolyte. We 
are indebted for our knowledge of it asa British species 
to Mr. Frederick Bond, an excellent ornithologist and 
entomologist, who obtained both sexes from the underside 
of the tail of thewhite Shrimp of the Sussex Coast, 
Pandalus annulicornis, in the month of April, 1846. 
Mr. Alder has also obligingly forwarded to us a spe- 
cimen of the male on Hippolyte Barleci, taken at Culler- 
coats, on the Northumberland Coast. So firmly was the 
little parasite attached to the ventral surface of the 
pereion between the fifth pair of pereiopoda, that it was 
