18 Gr. 0. Sårs. 



likewise from the outer side of the stem, the exopodite; 

 it is, however, most probable that in reality it does not 

 belong to the same segment as the former, but to the 

 next succeeding one (the 3rd). It has the form of a narrow 

 plate, which is drawn out into two opposite lappets, one 

 dorsal, the other ventral. The ventral lappet, which extends 

 about as far as the endopodite, is narrow linguiform, and 

 fringed all round with ciliated setæ. Inside the base of 

 this lappet is appended a peculiar triangular lamella, which 

 folds in upon the posterior face of the endopodite. In the 

 first pair of legs (fig. 9), this plate is rather small; but in 

 the succeeding pairs it considerably increases in size, assu- 

 ming a pronouncedly securiform shape, with both corners 

 drawn out to narrow lappets, the upper of which is the 

 larger (see figs. 10, 11). It is attached to the exopodite by 

 a narrow stalk, and has the distal edges fringed with a 

 number of finely ciliated setæ. In Estheria no such sharply 

 defined appendicular plate is to be found, though a slight 

 rounded expansion of the ventral lappet of the exopodite 

 may be demonstrated in some of the legs. The dorsal 

 lappet of the exopodite is somewhat different in the different 

 pairs of legs. In the first 2 pairs (see figs. 9, 10) it is 

 about half as long as the ventral one and somewhat curved, 

 with the tip bluntly rounded, and exhibits a very dense 

 fringe of short ciliated setæ. In the next succeeding pairs 

 it gradually increases in length, and in the 6th to 9th pairs 

 even considerably exceeds the length of the ventral lappet, 

 being drawn out into a thin lash, which is only provided 

 with short scattered bristles. In the 9th pair (fig. 10) this 

 lash reaches its maximum length, and has the form of a 

 quite smooth filament, which in the female attaches itself 

 to the anterior end of the egg-mass carried inside the shell. 



