16 



G. O. SARS. 



[Xo. 1. 



occurring unusiially far behind, and at first sight even posterior to 

 that of the antennæ. These organs exibit a very simple strncture 



j 



forming narr o w cylindrical stems, which are neither divided into 

 distinct articulations nor exhibit any trace of lateral lobes. The 

 extremity of each antennnla is slightly dilated and bears at 

 the tip a fascicle of very minute and delicate sensory filaments 

 (see fig. 6). Besides, a very fine ciliation is observed along the 

 outer part of the posterior edge. As to the size of the anten- 

 nulæ. they are somewhat shorter than the preoral subdivision of the 

 head, and when extended anteriorly scarcely reach to the end 

 of the blunt rostral part. They generally point straight down- 

 wards, bnt admit to a certain extent of being moved both anteri- 

 orly and posteriorly. 



The antennæ (Pl. IV, fig. 1), originating on the sides of 

 the head in front of the mandibles, are rather powerful organs. 

 They consist each of a strong flexible basal part. or scape, to 

 the end of which two elongate, joint ed branches are affixed. The 

 scape is rather short and thick, slightly elbow-shaped at the 

 base, and not reaching to the extremity of the head. It con- 

 sists of several imperfect joints, seven or eight in all, the last 

 somewhat longer than the preceding. On the upper side, each 

 of the four last joints is produced to a spiniferous process. The 

 first of these processes is very small and provided with only a 

 single small spine; the next is somewhat more projecting and 

 bears two stronger spines ; the third is very large and lamellar. 

 originating somewhat more exteriorly, with six strong spines 

 along its edge, and the fourth is also rather large, though 

 somewhat less projecting than the preceding, and provided 

 with five spines. Moreover, each of these joints has a spine 

 originating from the end on the inner side. All the spines 

 are more or less recurved, biarticulate, and finely ciliated 

 in their outer part. The branches are about twice as long as 

 the scape and nearly equal in length, both composed of seven 

 distinctly defined joints bearing on their lower edge slender cili- 

 ated bristles, on the upper strong spines. The upper branch is 

 a little stouter than the lower and distinguished by each of 



