Fig. 4. Balanus pseudauricoma Broch: a, outer side of tergum, X 15; b, outer side of scutum, X 15; c, 
inner side of tergum, X 15; d, inner side of scutum, X 15; e, labrum, X 62; f, mandible, X 50; g, maxilla 
I, X 50; h, distal part of penis, X 50. 
The compartments are smooth, wholly glossy 
white, without any colored stripes, but in 
younger specimens tinted with pink color all 
over. They are thick, solid, and finely ribbed 
longitudinally on the inner face. The base is 
radially ribbed, but not porous. 
The scutum has plain growth lines, widely 
separate, and exhibits no longitudinal striation; 
Broch found delicate, though distinct, longi- 
tudinal striation in the median part of the 
scutum on his specimens. This character is, in 
my opinion, of little value, as it is often found 
in other cirripeds. The articular ridge is absent. 
There is a faint indication of a pit for the ad- 
ductor muscle, as a small rounded depression, 
though it is sometimes lacking. There is, how- 
ever, no distinct pit for the lateral depressor 
muscle, although Broch recognizes its presence. 
The tergum exhibits a shape similar to that 
of Broch’s specimen. It has a shallow and wide 
furrow running from the apex to the end of the 
spur; according to Broch, however, "no spur 
fascicle or furrow but a narrow and distinct 
furrow runs parallel with the scutal margin 
limiting the spur area.” 
In both of the valves, the upper part of the 
inner face is usually roughened with many 
tubercles. The occludent margin of the scutum 
and the carinal margin of the tergum are some- 
times colored pale orange. 
The mouth parts exhibit all the peculiarities 
of B. pseudauricoma , especially the labrum, 
which has a very shallow notch and on each 
side of it seven or eight obtuse teeth (accord- 
ing to Broch, four or five) arranged irregularly. 
The mandible has five teeth of which the second 
