34 BRITISH ENTOMOSTRACA. 



those of the first pair, and having two or three short hairs 

 at the base of each joint. 



The organs of the month consist of one pair of 

 mandibles and two pairs of jaws. The mandible is 

 composed of a basilar portion, which is short and pro- 

 vided with two large teeth curved inwards, and a long 

 palpiform branch, formed of three joints, of which the 

 last two are much the longest. Behind these mandibles 

 we see a small inferior lip, consisting of two slender 

 scales ciliated on the edges, and united by a peduncle. 

 The first pair of jaws (t. II, f. 1 a) are formed of a 

 stout basilar joint, which has on its internal edge a 

 ciliated plate, and gives origin at one extremity to a long 

 filiform stalk, which is directed first forwards, then is 

 curved upwards and backwards, and is prolonged to the 

 extremity of the thorax, between the internal surface of 

 the carapace aud the flanks. This stalk is divided into 

 several articulations, each of which is furnished with long 

 hairs. The second pair of jaAvs have a very large basilar 

 joint, somewhat of a quadrilateral shape, the internal 

 edge of which is divided into several lobes, and strongly 

 ciliated, and the inferior edge gives attachment to two 

 branches, one of which is composed of two ciliated arti- 

 culations, and the other of only one. Succeeding these 

 organs of the mouth, we next find eight pairs of branchial 

 feet, inclosed entirely within the carapace (t. II, i. \ b). 

 They are of a foliaceous structure, are very slender, placed 

 very close to each other, and are attached to the eight 

 thoracic segments of the body. Each of these branchial 

 feet consist of three portions: 1st, a lamellar piece, 

 forming the internal branch, and occupying the whole 

 length, and which, of considerable size at the base, becomes 

 much narrower at its inferior half; 2d, a large mem- 

 branous plate, nearly as long as the internal branch, to 

 which it is attached at its upper external part; and, 

 3d, another membranous plate, placed between the two 

 preceding, and attached also to the upper and external 

 edge of the internal branch. 



