424 Wisconsin Academy of Sciences, Artsand Letters. 
diaptomus sicilis Forbes. 
Plate XVII, figs. 1, 4, 5, 9. 
1882. Diaptomus sicilis Forbes, p. 645 ; pi. VIII, figs. 9, 20. 
1884. Diaptomus pallidus var. sicilis Herrick, p. 142; pi. Q, 
fig. 18. 
1889. Diaptomus sicilis DeGuerne and Richard, p. 23; figs. 
13, 14; pi. II, fig. 18. 
1891. Diaptomus sicilis Forbes, p. 702; pi. I, fig. 6. 
1893. Diaptomus sicilis Marsh, p. 197; pi. Ill, figs. 8, 10. 
1895. Diaptomus sicilis Herrick and Turner, p. 60; pi. V, 
figs. 1-7; pi. XIII, fig. 18. 
1895. Diaptomus sicilis Marsh, p. 7; pi. VII, figs. 1, 11. 
1897. Diaptomus sicilis Schacht, p. 122; pi. XXI, figs. 1-3. 
1905. Diaptomus sicilis Pearse, p. 147. 
A rather small, slender species. The suture of the first cepha¬ 
lothoracic segment is very distinct. This segment is somewhat 
shorter than the rest of the cephalothorax. The last segment 
is armed with a minute spine on each side. 
The abdomen of the female is elongated. The first segment 
is shorter than the rest of the abdomen. It is moderately dilated 
laterally. Schacht figures small lateral spines, but I do not 
find them in my specimens. The second and third segments 
and the fureal rami are nearly equal in length. The fureal rami 
are more than twice as long as wide. The setae are long and 
slender. 
The antennae are 25-segmented and reach beyond the furca. 
The right antenna of the male is slightly swollen anterior to 
the geniculating joint. The antepenultimate segment bears a 
slender, straight process, slightly swollen at the tip, and nearly 
equal in length to the penultimate segment. 
The spines of the first basal segments of the female fifth feet 
are small. The lateral hair of the second basal segment is of 
moderate length. The first segment of the exopodite is twice 
