Te A. T. EVANS 
The large sinus found in each half of the basal trunk, branches 
with the muscle into the various parts of the appendage, finally 
ending in the extreme outer parts of the tip in small capillary 
tubes. After entering the head the sinuses bend toward the 
median line, pass between the two large retractor muscles from 
the frontal appendage and join in a single large sinus just back 
of the esophagus. 
The adipose and connective tissue areas in the smaller branches 
of the appendage are loosely arranged. Next to the muscle the 
adipose and connective tissues occupy more space in the append- 
age than any other. 
Summary of structures 
1. The appendage consists of a thin, chitinous, outer cover- 
ing; of columnar epithelial cells which may be simple, cuboidal 
or modified, the latter containing fibrils in their cytoplasm; 
of a large, longitudinal muscle in the ventral portion of the ap- 
pendage; of a large, ventral, crescentic sinus; and of areas of 
areolar, adipose, and connective tissues. 
2. The flexor muscle has its origin on a chitinous ridge just in 
front of the mandibles, and extends along the ventral part of the 
appendage, divides and subdivides in the various branches where 
it has its points of insertion on the floor and sides at the outer- 
most points. 
3. The sinuses arising in the tips as capillary tubes, extend 
along the ventral floor of the appendage below the large flexor 
muscle to a point just within the head, where they bend mesially, 
passing between the flexor muscles and extending to a point 
just posterior to the esophagus where the two join in a common 
sinus. 
COMPARISON OF THE FRONTAL APPENDAGE WITH THE INNER 
BRANCH OF THE SECOND ANTENNA OF OTHER PHYLLOPODS 
The second antenna of the Phyllopod, with its various modifi- 
cations found in the many different species, has been the subject 
of considerable study; and almost without exception the function 
of a clasping organ has been assigned to it. In some Phyllopods 
