20 



Gr. 0. SARS. 



[No. 1. 



anterior passing to the head, the posterior to the trunk (see Pl. 

 II, figs. 1, 2). The appendages of this division of the body are 

 only the two pairs of maxillæ, and hence it corresponds to the 

 maxillary segment in other Crustacea. Both these limbs are 

 distinctly defined in the present form, and lie close together, im- 

 mediately posterior to the mandibles (Pl. III, figs 4, 5, m 1 m 2 ). 



The posterior lip, or metastoma, on the other hand, would 

 seem to be very imperfectly developed. As a homologon to this 

 part, I regard two narrow linguiform lobes issuing far asunder 

 immediately in front of the anterior maxillæ (Pl. IV, fig. 4, x), 

 and on dissection generally obtained along with these maxillæ 

 (fig. 5, x). 



The maxillæ are very small and delicate organs, and rather 

 difficult to examine owing to their being firmly connected with 

 the ventral integument and also more or less concealed by the 

 first pair of legs. 



The first pair of maxillæ (fig. 4, m\ fig. 5) consist of a rounded 

 triangular basal part, bearing on the inner side a movable lam- 

 elliform masticatory lobe, generally doubled upon the basal part, 

 and provided at the free edge with a close series of slender 

 biarticulate and densely ciliated setæ, forming together a delicate 

 comb-like fan curving anteriorly toward the oral orifice. 



The second pair of maxillæ (fig. 4, m 2 , fig. 6) are considerably 

 smaller than the first and less strongly chitinized. They also 

 consist of an irregularly triangular or oval basal part and 

 a masticatory lobe, but the latter is less distinctly defined from 

 the basal part, and moreover is twisted in a peculiar manner so 

 as to expand in a plane nearly transverse to that of the basal 

 part. Along the rounded free edge of this masticatory lobe 

 .occur a series of biarticulate ciliated setæ, considerably shorter 

 however than those on the first pair, and also less curved. 

 On both pairs of maxillæ the masticatory lobe is moreover 

 covered with fine hairs on the lower side. 



