FRONTAL APPENDAGE—PHYLLOPOD CRUSTACEAN 73 
the second antenna is composed of a single, large basal joint 
and two distal, many-jointed branches. Estheria jonesii Baird 
furnishes an example of such a second appendage (fig. 5). An- 
other species which shows a different antenna is Streptocephalus 
texanus Packard (fig. 6) in which one of the branches of the 
large basal portion is found to be vestigial; the other branch is 
developed into a gnarled, tortuous, many (usually four or five) 
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Fig. 5 Second antenna of Estheria jonesii. (after Packard); A, ventral branch; 
B, dorsa] branch. 
Fig. 6 Second antenna of male Streptocephalus texanus; « 
B, specialized part. 
A, unspecialized; 
Fig. 7 Front of head of Chirocephalus diaphanus, showing the peculiar second 
antennae of the male (after Lankester);A, outer branch; B, modified inner branch. 
parted appendage, to which the function of a clasping organ has 
been assigned. In Chirocephalus diaphanus (fig. 7) the develop- 
ment seems to have gone a step farther and both branches of the 
second antennae are intact, but the inner branch is greatly de- 
veloped, consisting of a large main branch which is divided 
into several smaller parts. Near its point of attachment to the 
basal portion of the antenna proper a large fan-like division arises 
