19/ 



anterior margins of the protuberant parts. At the base of the third circus, the thorax bears a 

 tuft of long and numerous hairs, the free extremity ol which is directed backwards 



Fourth to sixth cirri have from 15 to 18 segments in each branch. The anterior face 

 of most segments bears four pairs of hairs (PI. XVIII, fig. 19); in some specimens, a few 

 segments, the y th — 9 th from the end, even bear a 5" 1 pair of extremely minute hairs. Group of 

 hairs disposed at the outer margin, and near the extremity of each segment; it has a single 

 longer hair, which, however, is considerably less than the length of the segment. 



Penis broad at the basis, growing narrow, and even very narrow towards the extremity. No 

 projecting point on the dorsal side of the penis observed. Penis very long, much longer than the cirri. 



Most specimens of this species, collected at different Stations, vvere found attached to 

 the spines of, probably, different species of Echinida. Often numerous, most of them small, 

 specimens are seen crowded together along the surface of the same spine. The species was 

 collected during the cruise of the Siboga at the following Stations : 



Stat. 49 a . April 14, 1899. Lat. 8°23'.5S., Long. H9°4'.6E. Sapeh-strait. Depth 69 m. Coral 



and shells. Numerous specimens. 

 Stat. 51. April 19, 1899. Madura-bay and other localities in the southern part of Molo-strait. 



Depth 69 — 91 m. Bottom : fine grey sand, or coarse sand with shells and stones. 



Numerous specimens attached to the spines of an Echinid. (Another sample 



from the same locality : Strait Molo, is from a depth of 54 — 90 m.). 

 Stat. 59. April 26, 1899. Lat. io°22'.7S., Long. 123 ió'-S E. Western entrance Samau-strait. 



Depth 390 m. Bottom: coarse coral-sand with small stones. A few dry specimens. 

 Stat. 302. February 2, 1900. Lat. io°27'.9S., Long. I23°28'.7E. Depth 216 m. Bottom: sand 



and coral-sand. 3 specimens without opercular valves. 

 Stat. 310. February 12, 1900. Lat. 8°3o'S, Long. Ii9°7'.s E. Depth jt, m. Bottom: sand with 



few pieces of dead coral. Group of small specimens attached to the spine of 



an Echimts. 



General Remarks. This species, according to Annandale's "On the Cirripedia" 

 Supplem. Report XXXI of Herdman's Report on the Pearl Oyster Fisheries of the Gulf of 

 Manaar, published 1906, Part V, p. 148, is found also in the Gulf of Manaar (Ceylon). It 

 was found attached to a piece of dead coral. Neither Borradaile nor Annandale inform us 

 at what depths their specimens were collected; I think we may conclude from this fact, that 

 they did not come from considerable depths. The Siboga dredged it at depths varying from 

 54 — 90111., and also in deep water, at depths of 216 and 390 m. I must point out, however, 

 that these specimens from greater depths (from Stations 59 and 302) are small and incomplete 

 (without opercular valves) and that their determination, in consequence, may always be considered 

 as somewhat uncertain. Species showing such considerable variation with regard to the depth 

 they inhabit, are not common in this genus; where it is the case we should ascertain if such 

 forms from different depths, which look as if they belong to the same species, do not show 

 more or less important differences in details of structure. In the present instance this was 

 impossible by the incompleteness of the specimens from deep water. 



Borradaile proposed for this species a new section of the genus Balanus. I explained 

 on p. 157 of this report why I could not agree with this proposal and what in my opinion 



would be a better subdivision of the genus. 





69 



