31 1 
with the basis, and the species exhibits a confusing external sim- 
ilarity with Balanus balanus (Lin.); it may indeed be a question, 
whether the statements as to the Antarctic occurrence of the last- 
named, Boreal and Arctic species are not due to erroneous ident- 
ifications of Balanus campbelli. — The carina has a more keel- 
like median ridge; a similar, although less pronounced ridge is 
Fig. 54. Balanus campbelli from Perseverance Harbour. a diagrammatic transverse 
section of the lateral compartment near the base, b—c external view of tergum and 
scutum, d—e internal side of scutum and tergum. [b—d X 5,3]. 
also observed in the ros trum. The carinal latus is narrow, 
only one third as broad as the lateral compartment, and about 
half as wide as the rostral compartment. — The compartments are 
porous, and the pores are, at any rate until shortly above the 
basis, covered by a transverse inner septum. In the carinal, and 
rostral compartments the walls between the pores stand forth as 
longitudinally striped ribs or fans of the interior lamina; in the 
lateral, and partly also in the carinolateral compartments these fans 
are pointing in the direction of the rostral side so that they cover 
the inner lamina in the basal part of the compartment (Fig. 54 a). 
— The sheath seems to be about half as long as the compart¬ 
ments; it is white. 
The rad i i are porous, but not very broad, with an upper 
margin parallel with the basis. The upper margin of the al ae is 
oblique and somewhat convexely arched. 
