Post-Abdomen — Legs. 325 
anteriorly. Laterally it has several bunches of stiff hairs. The 
terminal claws are placed on a prolongation from the anal lobe, 
which is very like the “End-stueck” of Moina or Ophryoxus , but 
much smaller. This prolongation bears two small teeth on each 
side. The terminal claws are slender, sharply curved at the end 
and finely denticulate. The teeth are of uniform size and there is 
no secondary tooth at the base of the claws. Anterior to the 
anus, the post-abdomen widens out rapidly with a semicircular 
margin and bears five to seven marginal hooked teeth, and later¬ 
ally, several rows of hairs extending from three or more of the 
teeth over about one-fourth the side of the post-abdomen. The 
abdominal setae are situated on no special projection. They are 
long, slender, sparsely plumose and bi-articulate. The margin 
of the post-abdomen between the abdominal setae and the anal 
spines is crenelated and bordered by short fine hairs. Ante¬ 
rior to the abdominal setae is a prominent abdominal process, 
consisting of a rounded ridge bearing a number of stiff hairs. 
Anterior to this is another lower ridge bearing several long 
hairs. These ridges fit into a fold of carapace and close the 
brood cavity. The dorsal part of the body possesses what Sars 
calls “mammilliform processes” similar to those in Macrothrix. 
MEASUREMENTS OF POST-ABDOMEN. 
Sense hairs to notch. 0.19 mm. 
Notch to terminal claws. 0.11 mm. 
Length of terminal claws. 0.06 mm. 
Greatest width of post-abdomen. 0.24 mm. 
Length of abdominal setae. 0.28 mm. 
LEGS. 
The nomenclature followed is that of Lund. * He divides the 
leg into two parts, the stem and two branches. In all cases the 
stem is short and scarcely distinguishable as a separate part. 
In an ideal leg, the stem would bear four processes. These 
* Bidrag til Cladocerernes Morphologi og Systematik, ved L. Lund; 
Naturhist. Tidskrift. Vol. VII, pp. 130-174, Pis. V-IX, 1871. 
