12 



G. O. SAES. 



[No. 8, 



jecting immediately behind the ones originating from the pre- 

 ceding joint; all the claws are finely denticulate at the posterior 

 edge and slightly exceed the length of the two outer joints ta- 

 ken together. 



The anterior lip, or labrum (see PI. Ill, fig. 3 and PL IV. 

 fig. 1), forms a rather thick, fleshy prominence of a rounded oval 

 form projecting between the bases of the lower antennae and 

 anteriorly covering over the oral orifice. It is finely ciliated 

 along the inferior and posterior edges and supported by several 

 chitinous stripes, the largest of which runs on either side at a 

 short distance from and parallel to the posterior edge. 



The posterior lip (ibid, and fig. 4) forms a thin, transversely 

 striated membrane supported by a pair of very strong chitinous 

 rods, each expanding at the end to a transverse plate armed at 

 the outer edge with a series of 7 strong horncoloured teeth 

 diminishing successively in size interiorly. Posteriorly the lip 

 joins a sternum-like vaulted plate, carinated along the middle 

 and placed between the bases of the 1st pair of mixillae. 



The mandibles (PL III, fig. 5, PL IV, fig. 1) are each com- 

 posed of a highly chitinised elongate corpus and a well deve- 

 loped pediform palp. The corpus is located on either side of 

 the body, immediately behind the base of the lower antennae, its 

 upper acuminate extremity being articulated to the inner sur- 

 face of the corresponding valve in front of the muscular 

 impressions of the great adductor, whereas the lower incurved 

 extremity is wedged in between the anterior and posterior lip. 

 The greater part of the corpus is hollowed to receive the power- 

 ful adductor muscles, and only the most inferior part, lying to 

 either side of the oral orifice, exhibits a more compact consistency. 

 The cutting edge is divided into several (about 6) strong, bi- 

 furcate teeth, diminishing in size interiorly, and between them 

 stiff bristles are seen to project. Besides, a short seta is 

 found attached to the outer side at some distance from the cut- 

 ting edge. The palp, originating from the outer side of the 

 corpus and extending anteriorly, forms a thick, fleshy, somewhat 

 pediform stem, curving downwards to either side of the labru© 



