180 BULLETIN 93^ U^-ITED STATES NATIONAL MUSEUM. 



but their place is taken by long spines, as in B. halanoides. This 

 differentiates B. glandula from B. crenatus^ which has the anterior 

 part of the segments of the third cirri set with short spinnles. 



B. glandula may most easily be distinguished from B. crenatus 

 hj the presence of a short adductor ridge in the scutum, with a con- 

 spicuous int^ like that for a muscle, below the confluence of the ad- 

 ductor ridge Avith the base of the articular ridge. The very short 

 broad spur of the tergum is also characteristic. In B. hesperlus 

 there is a prominent rugosit}^ between the adductor muscle pit and 

 the articular ridge, which is wanting in B. glandula. All of these 

 species, together with B. halanoides^ have terga of the same general 

 appearance, and the mouth parts and cirri do not differ very conspic- 

 uously. 



The pores in the basal edges of the parietes are irregular, not devel- 

 oped between all of the ribs of the interior; when developed the 

 inner lamina of the wall does not reach quite to the base. In full- 

 grown barnacles a few narrow pores may usually be found deep 

 between some of the basal ends of the ribs, which are crenulated and 

 unequal; but in some specimens they are wholly filled up, as in B. 

 halanokles. 



I take San Diego to be the type-locality. Plate 43, figures 1 to 3rt, 

 represent specimens from there. The shape is conic or convexly 

 conic, and the aperture is small in all the specimens seen. 



At La Jolla, California, I found B. glandula on rocks near high- 

 tide mark, with Mitella polymerus and Chtliarncilus fssus. 



In a group of nine individuals from San Francisco the shape is 

 more cylindric, and the walls are much more weakly ribbed, or in 

 some not at all ribbed. Aperture larger. 



A Puget Sound series, on valves of Mytilus^ contains strongly 

 ribbed, typical individuals, with others of a more cylindric shape, 

 with very weak ribs and large orifice. One is 13 mm. in basal diam- 

 eter, 12 mm. high. 



At Union Bay, Bayne Sound, British Columbia, elongated columnar 

 individuals occur with a shorter, obliquely conic form, growing upon 

 the large ones. In some of the shorter individuals the opercular 

 valves are unusually long, the tergal margin of the scutum decid- 

 edly surpassing the basal margin, as in figure 57^. The radii are 

 rather wide in some of this lot, but the compartments are thin and 

 weak (fig. 57). 



At Sitka the strongly ribbed conic and the smoother, short, cylin- 

 dric forms occur. The largest individual measures 16 mm. in basal 

 diameter, 13 mm. high. Cirri and mouth parts as described by 

 Darwin. See plate 43, figs. 5, 7, la. 



