66 PROF. G. 0, SARS ON THE COPEPODA [Jan. 12, 
Length of female (in last free stage) 0°50 mm. 
Remarks.—Vhis form is nearly allied to the preceding one, but 
of smaller size, and moreover easily distinguished by the rather 
different shape of the prehensile posterior antenne, the dactylus 
of which is unusually long and slender. The specific name here 
proposed refers to this last character. 
Occurrence.—A solitary female specimen of this form was 
found in the same sample in which the preceding species 
occurred. 
37. ERGASILOIDES BREVIMANUS, sp. n. (Plate XXIII. figs. 225— 
231.) 
Specific Characters.— FEMALE (in last free stage). Body 
(fig. 225) somewhat fusiform in shape, the head bulging con- 
siderably in its posterior part and gradually tapering anteriorly, 
front obtusely rounded. Dorsal face quite smooth without any 
trace of the peculiar sculpture found in the two preceding species. 
Segments of metasome evenly rounded laterally. Urosome 
(fig. 230) of a similar structure to that in the two preceding 
species. Caudal rami, however, distinguished by the seta of the 
inner corner being bifid, or divided near the base into two some- 
what unequal prongs, the outer one being the longer. Anterior 
anton composed of only five articulations, Posterior antennee 
(fig. 226) much shorter and stouter than in the two preceding 
species, with the propodus scarcely longer than the basal joint 
and quite simple; dactylus strong and somewhat dilated at the 
base, its terminal claw evenly curved and perfectly smooth. 
Natatory legs (figs. 227-229) with the outer two joints of the rami 
confluent. 
MALE (fig. 231) resembling in its external appearance that 
of H. megacheir, but at once recognisable by the bifid inner 
caudal sete. 
Length of female 0°62 mm., of male 0-47 mm. 
Remarks.—This form may be easily distinguished from the 
two preceding species by the different shape of the head in the 
female, the peculiar bifid inner caudal setz, and more particularly 
by the much shorter and stouter posterior antenne in the female, 
which latter character has given rise to the specific name here 
proposed. 
Occurrence.—Two or three females and one male specimen of 
this form were found ina sample from Tanganyika, taken 28/9/04 
at Mbete, south end of the lake. <A single female specimen 
occurred in a sample from Nyasa, taken 13/6/04 in Anchorage 
Bay. 
Genus Ercastnus Nordman. 
38. ERGASILUS sp. 
Occurrence.—A single female specimen (in the last free stage) 
of a genuine Hr gusilus, with distinctly 4-articulate urosome and 
