ON A NEW EPICARIDAN ISOPOD. 523 

 Length. Width. 



ist or proximal joint. 0,455 mm. 0,327 mm. 



2nd joint, 0,419 mm. 0,218 mm. 



3rd „ 0,255 mm. 0,164 mm. 



4th „ 0,291mm. 0,164 mm. 



Exposed length of the beak-like fifth joint, 0,091 mm. 

 Marsupial plates. Of marsupial plates there are five pairs. 

 Those of the first or foremost pair are of a somewhat complicated 

 structure and differ considerably in shape from all the other, each 

 plate of that pair being made up of two parts, the anterior and the 

 posterior, divided from each other by a distinct constriction (Pl. VII 

 Fig. 6). The anterior part is much the larger, it is folded so as to 

 present a small dorsal and a large ventral lobe. It is by the post- 

 erior inner margin of the former that the plate is attached to the body. 

 The posterior part of the plate is relatively small and narrow, its 

 posterior inner margin is provided with a series of a few (five or six) 

 short hair-like processes. The folded edge of the anterior part is 

 exposed to the outside, projecting far beyond the anterior end of the 

 animal, while all the remaining parts are hidden under the following 

 pairs of marsupial plates. Plates of the second pair are simple, each 

 presenting a more or less cup-like form ; the anterior margin is concave, 

 while both the inner and posterior margins are slightly convex. The 

 posterior margin as well as a part of the inner and outer margin are 

 provided with a series of short hair-like processes. The plate is 

 attached to the body by a part of its outer border, and is completely 

 covered over by the next pair, so that it is not at all visible on the 

 outside. The third, fourth and fifth pairs are generally similar to the 

 second in shape. However, in all these pairs the anterior margin of 

 the plates is not concave as in the second ; on the contrary, it is 

 slightly convex. The hair-like processes on the posterior margin of 

 the fifth pair are considerably longer than those of other pairs. The 

 marsupial plates gradually increase in size with every pair posteriorly, 



