317 
the great variability of the Balani, and the agreement in most 
characters with the two forms several times alluded to, very much 
speaks against our following that course. To settie the question 
it is moreover necessary to have access to a far larger material 
also of other forms of Balanus amphitrite than that which stands 
at my disposal. 
I have with some doubt referred two specimens from Kaladis 
Point, Mindanao, to the same form. The calcareous parts entirely 
agree with the Honolulu-specimens. But in other respects some 
differences have to be noted: In the 1 a b r u m there are only three 
or four a little larger denticles present on each side of the notch; 
in cirrus III the spines of the anterior side are a little more 
numerous, and the posterior spines smaller, in cirrus IV the dent- 
iculation of the anterior side is absent, and the posterior spines 
both here and in cirrus V and VI rudimentary. In spite of these 
differences, which point to a transition to the more common types 
of Balanus amphitrite, I have preferred not to establish a new form 
for the Mindanao-specimens which are evidently closely related to 
the Honolulu-specimens. 
Balanus minutus Hoek. 
Off Jolo; ab. 25 fathoms. 17/III 14. Several specimens attached to gor- 
gonarians etc. 
Off Jolo; 20- 30 fathoms. 20 III 14. Several small specimens together 
with Balanus amaryllis and Balanus amphitrite , some of them 
placed on Telesto sp. 
Off Jolo; ab. 15 fathoms; taken by a diver 21 /III 14. Three fine, small 
specimens on a flat stone, and two small specimens on a bry¬ 
ozoan. 
Although much speaks in favour of the opinion uttered by 
Pilsbry (1916) that Balanus minutus should only be regarded as 
a form of Balanus amphitrite, I have provisionally followed the 
course of Hoek (1913), and treated it as a separate species. 
The colours are rather richly varied from almost quite white 
with only light reddish lines or freckles to dark bluish-red with 
lighter stripes and spots. — The opercular plates (Fig. 58) indeed 
differ rather strongly from the common type of Balanus amphitrite. 
In the scuta there is no trace whatever of an adductor ridge, and 
in smaller specimens every trace of a pit for the adductor muscle 
