GREGARIOUS CRUSTACEA FROM CEYLON. 
19 
is identical with S. terebrans . It would be singular to have the 
same wood-boring isopod in Florida and Ceylon, and an almost 
identical but distinct species in Brazil and Madras. 
The sharp transverse ridge on the fourth segment of the perason 
is worthy of notice. There are generally four pairs of sub¬ 
median dorsal tubercles, successively on the sixth and seventh 
segments of the perseon, on the proximal sutured combination 
segment of the pleon and on the telsonic segment, the pair on the 
seventh pleon segment and the telsonic segment being flanked by 
another tubercle or tuft of setae on either side. But there seems 
to be some variation, and a definite determination of the tubercles 
is made difficult by the colouring which is often dark and by the 
clogging of the pubescence with extraneous material. The side 
plates of the second and following peraeon segments are distinct. 
The eyes are dark and wide apart. 
The first antennas have a stout first joint which may represent 
the true first and second coalesced. The following joint is short, 
scarcely longer than broad. The next is sometimes regarded as 
the third of the peduncle, but may be the first of the flagellum. 
It is as long as the basal joint, and is followed by eight small 
unequal joints. The second antennae have the last three joints of 
the peduncle subequal, the flagellum rather longer than the 
peduncle, tapering, of twelve to thirteen joints, many of them 
tufted. 
The strongly projecting mandibles are well described by Bate, 
though it is not easy to agree with his supposition that the feeble 
little tuft of serrated spines is employed “ in the tearing down of 
the wood into which the animal burrows.” As Miss Richardson 
intimates, the projecting incisor tooth provides a suitable equip¬ 
ment for this destructive work. The first joint of the small palp 
is the longest. 
The first maxilla have the inner plate tipped with three strong 
plumose setae and one that is feeble ; on the outer plate there are 
nine spines, all or most of them denticulate. Of the second 
maxillae the three plates are fringed along two-tliirds of the inner 
margin, the armature of the innermost plate being very distinctly 
plumose. 
The maxillipeds, which Bate speaks of as five-jointed, really 
have the full complement of seven joints, though the first and 
third are not very conspicuous. It should be noticed that these 
organs are built like those of Spliceroma serratum y but differ much 
from those in the genus Exosphceroma . 
Mr. Bate and Miss Richardson agree in describing the first three 
pairs of trunk legs (the first and second gnathopods and first 
