Remarks. This genus was established as early as in the year 1804 by 

 Latreille, and may be regarded as the type of the family. We know as yet 

 with certainty of only a single species, to be described below. Several other 

 species, it is true, have been named by M.M. Giard and Bonnier; but none of 

 them have been as yet described or figured in detail, and as they seem chiefly 

 to be established according to the different species of prawns in which they were 

 found, it is highly probable that their number will be greatly reduced and per- 

 haps combined into one and the same species. 



Bopyrus sqvillarum, Latr. 



(PI. LXXXIV. fig. 1.) 



Bopyrus sqrittaruni, Latreille, Hist. Nat. Crust. Vol. VII, p. 55, PI. LIX, fig. 2. 

 Syn. : Monocules craitgorum, Fair. 

 Bopyrus Fougerouxi, Giard & Bonn. etc. 



Specific Characters. Body of female broadly oval or pyriform in outline, 

 obtusely truncated in front, narrowly rounded behind, twisted sometimes to the right, 

 sometimes to the left, according to its place on the host. Cephalon subtriangular in 

 form, widening considerably distally, frontal edge nearly straight and continuous with 

 the side-contours of mesosome, lateral corners narrowly rounded. Segments of 

 mesosome with the lateral parts slightly elevated, each with a small indentation 

 in front of the posterior corner, defining sutures strongly curved. Median length of 

 metasome about half that of the preceding part of the body, epimeral plates slightly 

 bilobed, terminal segment of exactly the same appearance as the epimeral plates. 

 Male oblong oval in form, with the segments of mesosome well defined, those of 

 metasome confluent along the middle. Colour of female (according to Sp. Bate 

 & Westwood) pale greenish, with the head and incubatory lamella darker blackish. 

 Length of female 11 mm., of male 2 mm. 



Remarks. This form was first recorded by 0. Fabricius as Mono- 

 culus crangorum; but as the specific name proposed by that author involves a 

 confusion of shrimps with prawns, it is impossible to retain it and therefore, though 

 the older - one, it ought to give place to that proposed by Latreille. It is 

 the only as yet known species of the genus, for the several species named by 

 M.M. Giard and Bonnier cannot be admitted as such until it is clearly shown, 

 that in reality they differ specifically from the type species. It is very probable, 

 that~the present species infests several species of prawns and perhaps also 

 species of nearly-allied genera. 



