94 OUR CARCINOLOGICAL FRIENDS. 
of a light-green color, or nearly colorless, and often 
quite translucent. In this country they are not so 
highly esteemed as an article of food as they are 
in either England or France, where the prawn- 
fishery constitutes an important branch of industry. 
Our common shrimp (Crangon vulgaris, Pl. 7, Fig. 
8), which can be distinguished from the prawn 
(Paleemon, Pl. 7, Fig. 9) by the terminal joints of 
the two anterior pairs of legs being undivided, and 
by the filiform structure of the succeeding legs, does 
not appear to differ from the ordinary European 
species. It is abundant in the waters of the sandy 
flats, where by reason of its har- 
monizing coloring it escapes ready 
detection. Both shrimps and 
prawns are frequently infested 
with a loathsome parasite, which 
attaches itself as a round black 
mass on one side of the neck of 
the victim. This parasite is in 
itself a crustacean, known to nat- 
uralists as Bopyrus. 
A so-called shrimp, not to be 
confounded with either of the pre- 
ceding, is the Mysis stenolepis (P). 7, Fig. 1), which 
appears more abundantly about our coasts during 
the winter months. It may be distinguished from 
the true shrimps by its cloven or double feet, and by 
the external position of the gills. From the cireum- 
stance of its carrying its eggs in a pouch underneath 
the thorax it has received the familiar name of 
‘opossum shrimp,’ by which it is generally known. 
PANDALUS. 
