10 



The first maxillae (PL I., fig. 5) are tri-partite. The 

 protopodite is divided into two segments which extend 

 inwards as thin lamellae ; the lower is a flattish plate, 

 edged with a row of long curved setae, the upper is 

 unjointed, like the former, and hears on its distal end, and 

 also on the sides, a row of stout setae with a serrated lower 

 margin. The protopodite bears on its outer side a two- 

 jointed endopodite, the second joint of which is armed 

 near the end with transverse rows of short conical spines, 

 like the teeth of a saw. Along its outer edge it bears two 

 spines in G. 'pulex, three in G. locusta. 



The second maxillae (PI. I., fig. 6) consist of two flat 

 elongated plates, the inner, which may be the protopodite, 

 being a little smaller than the outer, which may be the 

 endopodite. Both are fringed, except on their outer 

 margin, by rows of long, curved, slender spines. 



The maxillipeds (PI. I., fig. 7) are fused by their 

 protopodites so as to form a lower lip, but the two seven- 

 jointed endopodites are free. The second and third joints 

 of the latter are produced on their inner margins into 

 large plates whicli bear spines similar to those of the 

 second maxillae. The last four joints can be easily 

 moved on one another, so that the last joint, which bears 

 a strong claw, may be bent right in and down in the 

 middle line. They are armed with strong spines and 

 bundles of setae. 



The gnathopods (PL I., figs. 8 and 9) are composed of 

 a two-jointed protopodite (coxopodite and basipodite) 

 bearing a five-jointed endopodite (ischiopodite, mero- 

 podite, carpopodite, propodite and dactylopodite), like the 

 rest of the thoracic legs. The propodites are large and 

 broad, that of the second gnathopod being rather more 

 quadrangular than that of the first in G. jyidex. In G. 

 locusta the propodite of the second gnathopod is m.uch 



