D2 
are considerably produced and extend beyond the end of the furcal joints. The other abdominal 
segments are entirely covered by the genital segment. The furcal joints are moderately long 
and cylindrical. The joints are nearly three times longer than broad and are furnished with 
an outer marginal seta (Plate LXV,. fig. 1). 
The antennules are short and are composed of five joints. The last joint is small. The 
whole of the distal margin of the first joint and the lower half of the distal margin of the 
second joint is fringed with short hairs. The third and fourth joints each bear one long 
sensory filament. 
The antennae, mandibles, maxillae and second pair of maxillipedes are similar to those 
of Peltidium purpureum. The first. pair of maxillipedes is similar to that of Aupeltedium glabrum. 
The exopodite of the first pair of feet is moderately long and slender. It is three- 
jointed. The second joint is distinctly longer than the first joint. The third joint is very short. 
It bears one stout and one slender curved claw. The endopodite is narrow and two-jointed. 
The second joint is furnished with one subapical and two apical setae (Plate LXV, fig. 4). 
The second, third and fourth pairs of feet are similar to those of Peltidium purpureum. 
The fifth pair is composed of a single highly chitinised and somewhat spiniform joint. 
The outer margin is furnished with three short setae. The inner margin is furnished with two 
setae at the base, and one at the middle. The apex is furnished with a short curved claw 
UglateeWOVe fie, 5). 
Male unknown. 
Occurrence. — One specimen was obtained from the surface plankton collected at 
Station 142, when the ‘Siboga’ was at anchor at Laiwui, on the coast of Obi Major. This species 
is named in compliment to my colleague Mr. James Jounstrone, B.Sc. His investigations and 
reports on the endoparasites of fishes have done much to revive the study and add to the 
knowledge of the British forms. 
28. Family PoRcELLIDIIAE. 
Genus Porcellidium Claus, 1860. 
The members of this genus are readily recognised by the very depressed body, and by 
the large flattened triangular first joint of the endopodite of the first pair of feet. The second 
joint is very short. It is furnished with two moderately strong claws that are densely fimbriate 
on one side. 
One species belonging to this genus was represented in the material collected by the 
‘Siboga’ in the Malay Archipelago. 
1. Porcellidium brevicaudatum Thompson & Scott. 
Porcellidium brevicaudatum Thompson & Scott, 1903, p. 275, pl. XII, figs. 11—14. 
A single female belonging to this species was found in the washings from dredged 
invertebrata collected at Station 273, at a depth of 13 metres. 
213 
