REPORT ON THE CIRRIPE1.MA. II!' 



About .six specimens were taken from the screw of II. M.S. Challenger when (April 

 1876) at St. Vincent, Cape Verde Islands, on her return homewards. 



Section C. Parietes and basis permeated by pores. Radii not permeated by pore-. 



Bali i, us trigonus, Darwin (!']. XII. fig. 20). 



Balanus trigonus, Darwin, Balanitis, 1854, p. 223. 



This species belongs to the section C of Darwin ; its parietes and basis are p< rmeated 

 by pores, its radii are not. The species was met with on two differenl decisions, and on 

 both only a couple of specimens were obtained, though they are, moreover, incomplete 

 (only one of them being furnished with opercular valves). I have not had the slightest 

 hesitation in considering them as belonging to the above-named species; the ribbed 

 parietes, the mottled purplish-red colour, the broad triangular orifice, are so highly 

 characteristic as not to be easily missed. Had there still remained any doubt, the 

 study of the scutum and tergum of the one specimen would have been sufficient to remove 

 it; the scutum is elongate-triangular, with one distinct longitudinal row of pits; the 

 tergum has no longitudinal furrow, the spur is truncated and very broad ; its width is 

 more than one-third of the width of the valve; the spur is situated very close to the 

 basi-scutal angle. 



One of the specimens from Port Jackson is not conical and depressed, but rather 

 cylindrical; the shape of its rostrum, moreover, is very interesting, the parietal portion 

 of the valve being strongly curved forward ; the tip of the lateral compartment 'itly 



curved in the same direction. Though this specimen has no opercular valves, it can 

 hardly be doubted, I think, that it belongs to the same species, because of th gular 



shape of the orifice, because of its colour and general appearance, and finally, though this 

 is of course not of essential importance, because of its being attached to other specimens 

 of the same species. The ribs on the parietes, however, are not so distinctly developed 

 as in the other specimens. I should not have insisted on this variation of the rostrum if 

 I had not recently had submitted to me for investigation some fossil specimens of a 

 species of Balanus from Tertiary deposits of Java which showed exactly the same shape 

 of the rostrum, and in general aspect quite resembled the specimen of Balanus trigonus 

 now under my inspection. Most probably Balanus trigonus may therefore be suspected 

 of occurring not only in the living condition, but also as a Tertiary fossil. 



The specimens collected by H.M.S. Challenger are partly from Port Jackson, 

 Australia, April 1874, depth 6 to 15 fathoms, and partly from Kobe, Japan, May 17 to 

 19, 1875, depth 8 and 50 fathoms. That the present species lives at a latitude north of 

 34° is a new fact in its geographical distribution. 



