366 A HISTORY OF EECENT CEUSTACEA 



Haswellia, Miers, 1884 (a new name for the pre- 

 occupied Calypfura, Haswell, 1881), has the last segment 

 of the perason produced into a broad plate or shield over 

 and beyond the pleon. The pleon has a terminal qua- 

 drangular notch, with a squarish lobe within it. The first 

 antennas are broad at the base. The type is HasLi-ellia, 

 carnea (Haswell). 



Ancinus, Milne-Edwards, 1840, has the body flattened, 

 the pleon triangular with a truncate tip ; the eyes dorsal 

 instead of lateral ; the first and second gnathopods sub- 

 chelate with long curved fingers ; the uropods with only 

 one branch, which is long and narrow, and, as in Ncvsq 

 and Campecopea, does not hug the telson. The single 

 species, Ancinus depress-as (Leach), exhibits considerable 

 diversity in the forms of the limbs of the perason. 



Scutuloidea, Chilton, 1882, has the body not very con- 

 vex, the peraeon much broader than the head, the pleon 

 broadly triangular, emargiuate at the apex, and the 

 uropods contiguous to it, very salient, single-branched, 

 consisting of a large squamiform plate. The type is 

 Scutuloidea maculata, Chilton, from New Zealand. The 

 second gnathopods are longer than the other limbs of the 

 peraeon. 



Plakarthrivm, Chiltou, 1882, has the body much de- 

 pressed, with the side-plates of the perason greatly ex- 

 panded, the first pair produced forward at the sides of the 

 head, and the seventh pair backwards nearly to the ex- 

 tremity of the uropods. The two basal joints of the first 

 antennas and the third and fourth joints of the second are 

 expanded, enclosing all the front of the head. The pleon. 

 is rectangular, with the uropods sub-terminal, the outer 

 branch short, apically dilated. Plakarthium typicum, 

 Chilton, found on the seaweed EHonia radiata, in Lyttel- 

 ton Harbour, New Zealand, ' affords a very good example 

 of protective resemblance, for the body being very flat and 

 of a brown colour can scarcely be distinguished from the 

 seaweed, to which it closely adheres.' Its position among 

 the Sphasromidas is somewhat doubtful, if it be the case 



