292 BARNACLES FROM DEEP-SEA CABLES. 



with their large and greatly expanded basal segment and short 

 cylindrical flagellum, is also most characteristic, though the number 

 of segments in the flagellum is variable. 



The characteristic features of the typical form are, as distin- 

 guishing it from both the two varieties discussed below, its compara- 

 tively narrow and compressed capitulum, the large size of the 

 calcareous plates on the upper part of the peduncle and the re- 

 latively considerable, though not excessive size of the peduncle. 



The type-specimens in the Indian Museum are from Bali 

 Straits (160 fathoms), while the examples in the Raffles Museum 

 are labelled, lat. 10° 22' 30" (S.?), long. 120° 7' 30" E., 130-500 

 fathoms. The latter do not exhibit the extreme gregariousness of 

 those figured in 1905. 



var. pellicatum, Hoek. 



1907. Scalpellum pellicatum, Hoek, Siboga-Exp., mon. XXXI a (Cirr. Pcd.) r 



p. 91, pi. vii, figs. 18, 19. 

 1909. Scalpellum sociabile var. pellicatum, Annandale, Sec. Ind. Mus. } III. 



p. 270. 



Hoek recognized the close relationship of this form to my 

 species, which was described while his ' Siboga ' report was in the 

 press, but left it to future investigators to ascertain the precise 

 connection. In view of the variations seen in the large series of 

 8. sociabile I have now examined, I am convinced that S. pellicatum 

 is no more than a variety of that species. The curious hook on 

 the upper margin of the capitulum, due to the fact that the apex 

 of the carina is entirely free from the capitular membrane, is per- 

 haps abnormal, but the form differs otherwise from the forma 

 tijpica in its relatively broad capitulum and short peduncle armed 

 with close-set plates. 



The specimens dredged by the c Siboga' (the only examples 

 known) were taken in the Celebes Sea and east of Halmaheira in 

 depths of 450 and 397 metres. They were probably all attached to 

 sea-urchins. I have not examined specimens. 



var. parviceps, nov. 



(PI. IV, fig. 2 ; pi. V, fig. 9 ; pi. VI, fig. 6) . 



This variety differs from the typical form mainly in its very 

 large peduncle, which is armed with relatively small, widely- 

 separated plates, in the strong development of the hairy capitular 

 epidermis and of the membrane in which the valves are buried. 

 The capitulum is also stouter and more quadrate and the valves 

 are relatively a little smaller. I figure the type specimen and also 

 its mandible and anal appendage. 



The measurements of the type-specimen are as follows. It is 



Jour. Straits Branch 



