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 

 antennae are short and apparently exarticulate, whilst the 

 lower pair of antennae 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 as a 

 parasite beneath the shell of a species of Hippolyte. We 

 are indebted for our knowledge of it as a British species 

 to Mr. Frederick Bond, an excellent ornithologist and 

 entomologist, who obtained both sexes from the underside 

 of the tail of the white 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 Barleei, 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 



