324 
HISTORY OF BRITISH CRUSTACEA. 
Gen. 181. NICOTHOE, Edw . fy Audouin . 
Two eyes ; antennse slender, many-jointed ; foot-jaws very 
small. Thorax of female enlarged on the side into two large 
wing-shaped lobes ; in the male these appendages are want- 
ing. There are four pairs of feet, which are two-branched 
and jointed. The body is jointed. 
The species of this curious genus is found attached, often 
in considerable numbers, to the gills of the common Lobster, 
and remains firmly fixed among the filaments of these organs. 
The male, according to Professor Yan Beneden,'* is much 
smaller than the female, and leads a free life, as does the 
young female at first : as soon as the latter fixes itself to the 
branchiae, lateral prolongations appear, to the height of the 
fourth thoracic ring. In the adult state these appendages 
seem to form the whole animal. 
Nicothoe astaci, Aud. & Edw. Lobster Louse . (Plate 
XX. fig. 1.)— Of a rosy hue, about a line long. Dr. Baird 
has found it on the gills of the Lobster in the London 
market in March and April, and Mr. Cocks in a Lobster 
taken at Ealmouth, in September. 
* Memoire sur le Developpement, etc., des Nicothoes, in vol. xxiv. of 
the Memoires de l’Academie Royal e de Belgique. 
