of the French Coasts. 165 



of the body, in cacli segment except the first, the white branch- 

 ing reproductive organs are seen shining through the skin. 



On the lower surface of the body the foremost organs arc 

 two pairs of short antennas placed obliquely on the sides of 

 the head, and scarcely passing its margin. The superior an- 

 tenna is shorter than the other, and of three joints ; the inferior 

 antenna has four. The antennas of each side spring from a 

 common fiat basilar piece. 



The buccal apparatus is of a somewhat conical form, with the 

 apex, bearing the buccal orifice, directed forward. The organs 

 of the mouth consist of two pairs of hard corneous denticulated 

 jaws, forming a sort of curved nippers, of four other small foot- 

 jaws, each consisting of three joints and terminated by a crooked 

 claw, and of two flat pointed laminae forming a lower lip. The 

 thoracic legs consist of five joints, of which the femoral and the 

 apical are the largest ; the latter is terminated by a powerful, 

 curved, and denticulated claw, which, by folding down upon a 

 protuberance of the lower surface of the inflated apical joint, 

 becomes a prehensile organ. The body is of a buff colour, with 

 the abdomen reddish brown. The intestinal canal is brick-red, 

 with a fine white line upon it, indicating the course of the in- 

 terganglionic cord. The surface is covered with short, rigid, 

 and scattered hairs. 



The female is much larger than the male, measuring 7 mill, 

 in length by 3 mill, in breadth; its form is a regular oval. 

 The head is hemispherical, and embraced by the first pair of 

 incubatory plates, of which there are in all four pairs, increasing 

 in dimensions as they descend towards the abdomen. The last 

 two plates are longer than the others, and their posterior margin 

 is turned down almost perpendicularly upon the base of the 

 abdomen so as to close the incubatory chamber. At their base 

 these plates present small niche-like cavities for the reception 

 of the feet. 



The epimeric pieces are alternately large and small, so as to 

 facilitate the movements of the thorax ; from the fifth onward, 

 they become more and more pointed to the extremity of the 

 abdomen. Each of the five segments of the abdomen is pro- 

 vided on each side with a branchial lamina, which is very deli- 

 cate and contractile ; these lamina?, like the segments to which 

 they are attached, diminish in size posteriorly. 



The ventral surface is nearly fiat, or very slightly concave. 

 The buccal apparatus is placed close to the membranous anterior 

 margin of the head ; the orifice is pierced in the middle of a 

 large lip, and from it issue two pointed denticulated jaws, form- 

 ing a pair of pincers. A little above this orifice are situated 

 the antennas, which, as in the male, are four iu number j the 



