330 
The most nearly related species is evidently Balanus navicula\ 
but the deeply incised marginal edge of the opening, and the ex- 
ternal, digitiform tooth of the carina distinguish it from all other 
species of the group. 
Genus Acasta Leach. 
Acasta cyathus Darwin. 
Off Jolo; ab. 12 fathoms, 17/III 14. Several small specimens together 
with Acasta Dofleini. 
The specimens are small, the larger ones with a greater basal 
diameter of only 4,2 mm and a carinal height of 4,2 mm. There 
is no longitudinal striation in the scuta, but in all other details 
the specimens agree with Darwin’s (1853) and Pilsbry’s (1916) 
descriptions; the armature of the cirri agrees with Pilsbry’s spec¬ 
imens. 
Acasta japonica Pilsbry. 
Sagami Sea; 400 fathoms. 1—7/V 14. Two small, partly broken spec¬ 
imens in a small fragment of a sponge. 
Acasta pectinipes Pilsbry 
(== Acasta nitida Hoek 1916). 
Off Jolo; ab. 25 fathoms, sand and coral. 20 /111 14. One specimen. 
Acasta conica Hoek. 
Off Jolo; 20-30 fathoms, sand and coral. 20/III 14. One specimen to¬ 
gether with Balanus ampliitrite, Balanus minutus, and Balanus 
amaryllis. 
The rostro-carinal basal diameter is only 4 mm. The plates all 
over their surface show distinet striae of growth, in the basis par¬ 
allel with the periphery, in the compartments parallel with the 
basal margins. The radii are densely vertically striped without 
the feeble horizontal stripes mentioned by Hoek (1913); this is 
the only difference from Hoek’s specimens which could be found 
in the specimen at hånd. 
Acasta Dofleini Kriiger. 
Off Jolo; ab. 12 fathoms, hard bottom. 17/III 14. Three small specimens 
together with Acasta cyathus. 
