ARTHROPODA. 33 



IV* pair. (Mandibles) 



Each mandible carries a jointed palp, which corresponds to 

 the terminal joints of the mandibular ' endopodite ' (Huxley). 

 The calcified rod projecting outwards is the tendon of the ad- 

 ductor muscle of the mandibles. 



III d pair. (Antennce.) 



The antennae are composed of a short basal ' protopodite/ 

 which carries a long multi-articulated 'endopodite' and a short 

 flattened scale-like 'exopodite.' The black arrow is inserted into 

 the orifice of the duct of the 'green gland.' 



IP pair. (Antennules.) 



A three-jointed ' protopodite ' is succeeded by two long 

 multi-articulated filaments, the 'exopodite' and 'endopodite.' 

 An aperture protected by membrane in the proximal joint, and 

 towards which the arrow points, is the auditory organ. 



/" pair. (Ophthalmic peduncles) 



The eye-peduncles are composed of two segments, the distal 

 one of which carries the eye itself. 



On the left of the specimen is a portion of the skeleton of a 

 female, with the ventral surface turned upwards, so as to shew the 

 openings of the oviducts on the ' protopodite' of the third pair of 

 ambulatory legs. The two orifices are indicated by two black 

 arrows. The first pair of post-abdominal appendages differs 

 from those of the male in being simple unmodified filaments. 



The structure of the stomach is illustrated by the two 

 specimens marked A and B. In B the greater portion 

 of the cephalothorax has been removed so as to expose 

 the cavity of the thorax, with the stomach in its natural 

 position. This viscus occupies nearly the whole of that part of 

 the cavity which lies in front of the cephalic suture, and its 

 membranous walls are supported and strengthened by a some- 



CL. 3 



