BOPYRHXE. 211 



male also of a pair of mandibles deferentiated into a 

 pointed siphon-like organ, the two appendages meeting 

 together in a slight twist, and so strengthening each other 

 as a penetrating organ, which is protected by one or two 

 pairs of broad fleshy scale-like maxillae, of which the 

 first pair is generally bi- or tri-articulate, and the others 

 almost without trace of articulation, and united for the 

 most part to the under surface of the head by a small 

 joint. 



The legs are very short, having a broad hand strongly 

 hooked at the tip for prehension ; in some of the species 

 the full-grown females lose the greater portion of these 

 limbs. They are furnished with large incubatory plates 

 on the underside of the body : in some species, however, 

 they have the appearance of being recurved, and of 

 covering the upper side of the animal. (See Hesse, Ann. 

 Sci. Nat. ser. 5, t. iii. p. 237, where this, and t. iv. p. 226, 

 where the reverse is stated to be the case.) 



The tail (pleon) generally forms a distinct portion of 

 the animal, and is composed of a series of short segments, 

 which are often furnished with elongated lamellae, or other 

 analogous appendages, most conspicuous in the female. 



The male is always very small, and much narrower 

 than the female, with the head and seven segments of 

 the body distinct, and each segment is furnished with a 

 pair of short legs formed like those of the female, but 

 more slender ; the tail (pleon) is also more elongated, with 

 the joints often distinct; the eyes are also distinct in 

 the males, although only rudimental or wanting in the 

 females. 



The young of these animals are of an oval form, not 

 unlike that of a wood-louse, having the segments of the 

 tail of a comparatively larger size than in the adult state ; 

 in the typical genera they are furnished with two pairs of 

 antennae, of which the anterior are short, but the posterior 



P J2 



