316 
has proceeded one step further; the bristles are decidely arranged 
in påirs, generally four or five; but also here the anterior surface 
is covered with small wharts or denticles, although of a minute 
size. The posterior short spines are also present here, and are kept 
in cirrus V and VI, here even increased in numbers to three on 
each segment. 
In its mouth-parts the present form more approaches the 
forma albicostata. The crest of the la brum is armed with num- 
Fig. 57. Balanus amphitrite f. hawaiiensis from Honolulu. a labrum, b mandible, 
c seventh segment of cirus III, d sixth segment of cirrus IV, e lifteenth 
segment of cirrus VI. [a—b X 44, c—e X 67]. 
erous denticles at the notch, the sides of the latter carrying very 
short fine hairs. While the maxi 11a corresponds with the forma 
albicostata , the mandible (Fig. 56b) differs; the drawing is from 
a specimen about moulting, and the internal contour gives a fairly 
good idea of some details of the pectinate lower part, which are 
all but worn off in the old cuticle: below the small fourth tooth 
the edge is finely denticled, tending to a comblike structure, with 
one larger denticle placed in the middle of the pectination. This 
denticle and the small „fourth tooth“ are of the same size. 
We might feel inclined to think that these characters are so 
important that the specimens ought to be taken as the type of a 
separate species. If on the other hånd we take into consideration 
