Birge—Notes on Cladocera. 
1027 
southern coast of the United States is another case of the ex¬ 
tension into that region of South American forms. 
From this description the following account may be given 
of Pseudosida. 
Genus. Pseudosida, Herrick 1884. 
General form much like Sida , but head more depressed and 
rounded and dorsum more arched. Ho fornix or cervical 
glands. Head with rostrum wider and less pointed than that 
of Sida, but having much the same form and position. Cer¬ 
vical sinus present. Antennules inserted or elevations on 
side of rostrum; basal part very long, stout, curved; olfactory 
setae sessile or on finger-like projection on posterior side, 
nearer insertion than distal end. Distal end notched, and 
from it arises a very long, slender, flexible flagellum, longer 
than basal part, sparsely provided with long, fine hairs. An¬ 
tenna stout, much like Latonopsis, base with two stout, short, 
curved, thorn-like spines, and usual sense-setae; dorsal ramus 
2-jointed, ventral 3-jointed. Setae ~ of various 
lengths; the longest is that on the second joint of the ven¬ 
tral ramus, which may equal % of the total length of the 
animal, but is often broken*. The terminal joint has one 
very large seta; others much smaller and one or more often 
lost. Spines - Q ^ 1 > those of dorsal ramus large and some¬ 
what hooked at the tip; that on second joint of ventral ramus 
large. Valves elliptical; posterior margin rounded over into 
ventral; anterior margin concave and joins ventral in a well 
marked angle. Free margin fringed with long, movable setae, 
much less developed than in Latona and not especially elon¬ 
gated at infero-posteal angle. Post-abdomen large, with long 
abdominal setae on separate papillae. Claws, large, stout, 
curved, with two long basal spines and a very small one prox- 
* Dr. Von Daday has been so kind as to send me a specimen of 
P. szalayi, which shows that the inequality of the antennary setae of 
that species is quite as marked as in P. Mdentata. The specimen is not 
that of a full grown animal, and the longest set equals 70% of the total 
length of the head and valves. 
