313 
in a single row; these spines are as large as, or even larger than 
the tipper spines; the lower angle carries some few, more hair- 
like bristles. On the sides of the blade a single row of somewhat 
thicker hairs runs parallel with the edge along the part, carrying 
the paired spines; the outer part of the blade below this row is 
furnished with finer hairs. 
The cirri exhibit the same type as in Balanus tintinnabulum 
Lin., and Balanus algicola Pilsbry; cirrus II, and III are short, 
Fig. 55. Balanus campbelli from Perseverance Harbour. a labrum. 1) mandible, 
c maxilla, d seventeenth segment of cirrus IV. 
[All figures X 22]. 
the latter shorter than the other cirri but with a comparatively long 
pedicel. 
In cirrus I the rami have 12 and 18 segments, the shorter 
ramus being only half as long as the other one. Cirrus II has 
subequal rami with 12 and 13 segments; the somewhat shorter 
rami of cirrus III have 13 and 14 segments and are only slightly 
different in length. 
The segments of the three posterior cirri have four pairs of 
long spines at their anterior side. In cirrus IV the segments how- 
ever are a little swollen; the segments at their anterior and distal 
side are armed with a single, arched row of denticles. In the basal 
segments of the rami the row is doubled, or the denticles even 
may be found irregularly crowded beside the base of the upper 
spines. 
The penis is annulated and short, not reaching half the length 
of cirrus VI; it has some 5—6 scattered small hairs on its distal 
third, but no tuft of hairs at its distal end. 
