THE SESSILE BARNACLES. 



301 



distinguishable from the latter, even at considerable distance. Thus, the con- 

 fusion of the two, said to have been commonly made by English collectors, 

 seems incredible here. The largest specimens which I have seen have not 

 exceeded 10 mm. in diameter at the base. 



I am treating this form as a species because many specimens from 

 localities scattered over a wide area agree fully in the characters 

 differentiating it from stellatus. These specimens, moreover, are 

 seated upon widely diverse materials stones, shells, coconuts, and 

 rushes indicating that their peculiarities are not due to a special 

 environment. The rounded prominence of the articular ridge of the 

 scutum, tapering downward, and the broader spur of the tergum are 

 characteristic. 



It is .quite possible that the specimens from Albatross station 2004 

 were picked up by the trawl at the surface, for one could not expect 

 Chthamalus on a rush from a depth of 102 fathoms. If really from 

 the bottom, the rush on which they were seated certainly floated 

 there and sunk, through becoming water-logged. The barnacles were 

 living when collected. The station is at the edge of the continental 

 plateau, where flotsam brought by the Gulf Stream might naturally 

 be expected to settle. The specimens agree entirely with those figured 

 in plate TO, figures 1-1^7, 4. 



CHTHAMALUS STELLATUS (Poll). 



1791. Lepas stellatus POLI, Testacea utriusque Sicilian, vol. 1, p. 29, pi. 5, figs. 



18-20. 



1S03. Lcpas punctatus MONTAGU, Testacea Britanica, p. 8, pi. 1, fig. 5. 

 1818. Chthamalus stellatus Poll, RANZANI, Opuscoli Scientific!, vol. 2, p. 84, 



pi. 3, figs. 21-24. 

 1839. ? Chthamalus vitretis COSTA, Fauna di Napoli, Cirropedi, p. 27 (on pumice, 



from Lipari?) 

 1854. Chthamalus steUatus DAKWIN, Monograph, p. 455, with var. communis, 



pi. IS, figs. Iff, c. e. /. h; var. fragilis, fig. Id; var. depressus Poli, figs. 



1&, 0, h. 

 1905. Chthamnliis stellatus, var. fistulosus GRUVEL, Monographic des Cirrhipedes, 



p. 201. 



Distribution. Eastern coast of the North Atlantic and Mediterra- 

 nean ; type-locality, the Bay of Naples. Littoral, on rocks and shells. 



In the Darwinian limits, this species is widely spread in the east- 

 ern and western Atlantic and the oriental region. 1 It is a group of 



1 Darwin also mentions " Oregon or northern California " among the localities for 

 C. steUatus. 



