BOPYRUS SQUILLARUM. 221 
the body. The respiratory scales on the underside of 
the tail are short and transverse; the basal segment of 
the tail is much shorter than the following, the second 
and three succeeding being of equal size, whilst the 
sixth is rather narrow and nearly truncate, without any 
appendages. : 
The female when alive is of a pale greenish colour, 
glossy above, with the head and_oral plates black, and 
those of the ovisac and under surface of the head black 
or very dark at their edges. 
The young Bopyri, before they leave the incubatory 
pouch of the females, are ovate in form, and dorsally 
convex, resembling very minute wood-lice, with the 
outer pair of antennz greatly elongated, composed of 
four joints, of which the first is short and robust, and 
the others elongated and terminated by one or two very 
long and slender setzz. The legs are broadly sub-cheli- 
ferous, especially the four posterior pairs, the three 
anterior pairs being rather more slender and directed 
forwards, whilst the four latter pairs are directed back- 
wards. The respiratory scales of the tail (pleopoda) are 
strongly setigerous, the posterior pair being composed 
of a very short basal joint, supporting two elongated 
rami, pointed, and tipped with one or two terminal 
sete. 
The females of this species are attached to the outer 
lining of the branchial cavity of the common prawn, a 
single parasite being found upon an individual prawn. The 
fecundity of these parasites is very great, the eggs being 
retained within the incubatory pouch where they are 
hatched, and M. Risso states that he had counted as 
many as eight hundred young ones nourished by a single 
female. 
Mr. Adam White, upon the authority of Col. Mon- 
