THE SESSILE BARNACLKS. 



181 



Unalaska specimens are strongly ribbed, with decidedly wider radii 

 than those of southern California. The bases of the parietes show no 

 pores, but traces of them may be seen externally in some compart- 

 ments. Opercnlar valves (pi. 43, figs. G, Get-) like Sitka specimens. 



Atka specimens are similar to those of Unalaska in the Avails, but 

 the opercular valves are peculiar, unlike any other lot examined. 

 The scutum is very wide and short, the tergum is unusually narrow 

 in contour, but this is largely due to corrosion (pi. 43, figs. - to 



FIG. 57. BALANUS GLANDULA FROM UNION BAT, BAYNE SOUND, BRITISH COLUMBIA, a, 6, c, 



SCUTAL, INTERNAL AND EXTERNAL ASPECTS OF THE TERGUM, AND d, C, INTERNAL AND EX- 

 TERNAL ASPECTS OF SCUTUM OF THE LONG INDIVIDUAL IN THE GROUP /. J/, SCUTUM OF A 

 SHORT INDIVIDUAL IN THE SAME LOT. 



The individual I dissected from Atka has the first cirri quite un- 

 equal, posterior ramus of 10 segments not quite two-thirds as long 

 as the anterior of 1C. Second pair subequal, of 10 and 11 segments. 

 The posterior cirri have six pairs of spines on a segment. Penis long, 

 with a dorsal point near the base. 



Balanus glandula has been reported from the " southern Pacific 

 Ocean attached to Pollidpes polymerus" (Darwin, Monograph, 

 p. 266), on the evidence of specimens in the British Museum labeled 

 as having been collected by Sir James Eoss in course of his Antarctic 

 Expedition. Such distribution seems highly improbable. Until 

 confirmed by new records it may be put in the doubtful list. 



4720 Bull. 9316 13 



