Chilton. — Additions to the Neiv Zealand Crustacea. 75 



radiata. It affords a very good example of protective resemblance, for the 

 body being very fiat and of a brown colour can scarcely be distinguished 

 from the seaweed, to which it closely adheres. It has several appliances 

 which enable it to cling tightly to the seaweed ; in the first place all the 

 legs are furnished at the ends with powerful hooked claws, then on the 

 under side of the basal joint of last pair of pleopoda and round the proximal 

 edge of the outer branch are strong hooked setae, and besides tbis, on the 

 basal joints of all the legs, on some parts of the under surface of the head 

 and in one or two other places, are small projections of the integument 

 which may possibly be hooked setae, though their nature is not very 

 apparent, but which certainly appear to have the same function. They 

 are shown on the basal joints of the legs in fig. 5 d and /. 



In the mouth parts the maxillipedes appear to have the same form as in 

 Sphceroma, etc., consisting of a long slender basal portion bearing an ap- 

 pendage of four joints, none of which is produced into a lobe at the distal 

 end. The maxillae I have not made out satisfactorily. The mandible is 

 long and slender and has a sharp cutting edge of four teeth, and below two 

 setae with stout bases. There is no appendage unless a rounded protuber- 

 ance on the mandible itself is to be regarded as such (fig. 5 c). 



The branchial plates — pleopoda — rest in a slight hollow formed by the 

 arching of the abdomen. There appear to be two distinct kinds, the first 

 (fig. 5 g) consists of a short basal joint bearing two long subequal joints, 

 each of which bears several long plumose setae ; in the second (fig. 5 h) the 

 basal joint is about twice as broad as long, the inner branch is short and 

 triangular, the inner edge straight and the outer one slightly curved, it has 

 no setae except a few exceedingly delicate ones along the inner edge ; the 

 outer branch is of the same length as the inner, and is curved so as to fit 

 along the curved outer edge of the inner branch, it bears short plumose setae 

 along its outer edge, these start about half-way along the joint, and are at 

 first very small, but gradually increase in size till the end where they are 

 largest. 



When viewed from above the last pair of pleopoda appears to be articu- 

 lated on to the abdomen at its posterior edge, but when seen from below it 

 will be found that the basal joint extends anteriorly along the under side of 

 the abdomen, and no doubt belongs as usual to the sixth segment of pleon, 

 which is, together with the others, completely united to the terminal one or 

 telson. 



At the end of the abdomen, in the centre, there is a small opening 

 formed by the posterior edge of the abdomen being slightly arched and thus 

 raised a little above the inner branch of the last pleopod ; at this opening is 

 a kind of strainer formed by setae on the posterior edge of the abdomen and 



