326 
been dead for a long time, so that every trace of their bodies, 
and the opercular plates has disappeared. 
Balanus pvovipiens Hoek. 
6 miles N. N. E. of Sacol, Mindanao; ab. 35 fathoms, 6/III 14. One small 
specimen on a threadlike gorgonarian (probably Scirpearella sp.). 
Off Jolo; ab. 25 fathoms, 17/III 14. Numerous specimens in a stouter 
gorgonarian (a red Mopse Ilid), together with Smilium acutum. 
While the Sacol-specimen has the same low and stretched shape 
as Hoek’s specimen, the specimens from Jolo are comparatively 
much shorter and higher (Fig. 63). 
This evidently depends upon the 
gorgonarian which in each case 
serves as participant of the symb¬ 
iose: a siender gorgonarian with 
thin coenosarcal layers makes the 
cirriped develop into a siender and 
long specimen, whereas the same 
species in fleshy gorgonarians at- 
tains a broader and higher shape. 
The Jolo-specimens are purely 
white with a rather glossy surface 
when the covering tissues of the 
coral are removed, whereas the Sacol-specimen has the reddish 
colour-tinges mentioned by Hoek in the „Siboga“ -specimen 
(1913). — An examination of the interior parts of the shell re- 
veals the same features as found in Balanus cymbiformis by Dar- 
win (1853): „The parietis are strongly ribbed internally, and are 
not permeated by pores. The basal cup is not porose, but its inner 
surface is ribbed in lines radiating from the centre." Hoek points 
to the near relationship between Balanus proripiens and Balanus 
cymbiformis, and it may indeed be a question, whether they are 
specifically separable; a reexamination of Darwin’s type spec¬ 
imens will have to settie this question. 
Balanus dentifer n. sp. 
Fig. 63. Balanus proripiens, off Jolo. 
The coenosark of the gorgonarian al¬ 
most entirely prepared off. [x 4]. 
32° 15' N., 128° 12’ E., 90 fathoms. „Hyatori Maru“ 15/V 14. Several 
specimens in octocorals of the families I si idae, and Muri- 
cæi d ae. 
