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total length of the second joint. The third joint is very small. The endopodite is equal to 
twice the length of the first joint of the exopodite. The second joint is small and shews no 
trace of division to indicate a third joint. The terminal claws of the exopodite and endopodite 
are of the normal Harfpacticus type (Plate LXI, fig. 6). 
The second, third and fourth pairs of feet are nearly similar to those of Harpactecus chelifer. 
The fifth pair of feet is rather slender. The inner portion of the basal joint is very 
little expanded. It is furnished with three marginal and two apical setae. The distal joint is 
comparatively narrow and elongate. The distal portion of the outer margin is furnished with 
two rather strong spines. The joint is also provided with one outer marginal seta, one apical 
seta, and one inner marginal seta (Plate LXI, fig. 7). 
Male unknown. 
This species is quite distinct from any of the known members of the genus. It can 
readily be recognised by the well defined dorsal crest on the cephalic segment. The second pair 
of maxillipedes is not of the normal H/arfacticus type, but in the absence of a male it is 
perhaps well for the present to regard the species as a member of the genus Harpacticus. 
Occurrence. — One specimen was obtained from the plankton collected at Station 
35 (Paternoster Islands), on March 28th. 
2. Harpacticus clause nov. sp. Plate LXI, figs. 9—14A. 
Female — length .67 mm. 
Seen from above, the body appears rather slender and slightly depressed, with a moderately 
prominent rostrum. Viewed from the side, the distal ends of the ventral margin of the cephalic 
and thoracic segments appear narrowly rounded. , 
The abdomen is composed of four segments. The combined length of the abdominal 
segments and furcal joints is. contained fully twice in the total length of the cephalothorax, 
from the apex of the rostrum to the end of the last thoracic segment. The genital segment 
is as long as the combined length of the next three segments. Its ventral surface is traversed 
by a distinct suture. The second segment is as long as the combined length of the third and 
fourth segments. The fourth segment is short. The furcal joints are only half as long as broad. 
The antennules are composed of nine joints and are of moderate length. The combined 
length of the last five joints is equal to one-third of the combined length of the first four 
joints. The second last joint is very small. | 
The antennae, mandibles, maxillillae and maxillipedes are of the normal Harpacticus 
type. The second pair of maxillipedes is very similar to that of Harfacticus uniremis Kroyer. 
The four pairs of swimming feet are similar to those of Harpacticus gracilis. The second 
joint of the exopodite of the first pair of feet is rather shorter than the first joint. The endopodite 
is very little longer than the first joint of the exopodite (Plate LXI, fig. 14). 
The fifth pair of feet is moderately large. The inner portion of the proximal joint is 
considerably expanded. The distal end of the expansion is broadly rounded. It is furnished with 
two subapical spines and one outer marginal spine. There is a considerable space between the 
inner marginal spine and the inner subapical spine. The surface of the expansion is furnished 
20T 
SIBOGA-EXPEDITIE XXIX@. 26 
