THE SESSILE BARNACLES. 



177 



Tips of the terga and scuta diverge conspicuously, as in typical 

 curviscutum, and the scutum is very concave between apex and base. 

 The articular ridge is longer and more widely reflexcd than in the 

 type. The tergum is wider, with longer carinal margin, but the spur 

 is Harrow. 



The labrum has three acute teeth on each side of the notch. Max- 

 illa about as in typical curviscutum. 



The posterior ramus of the first cirrus is about three-fifths the 

 length of the anterior. Cirrus ii with subequal rami of 8 segments. 

 Cirrus iii has slightly unequal rami of 10 and 9 segments. Part of the 

 segments of the outer ramus have a few spinules and flat, multifid 

 scales near the anterior and distal borders (fig. 55). The last 

 cirri have 21 segments, bearing 5 pairs of spines. The spines at the 

 distal posterior angles are nearly or quite as long as the segments, 

 or sometimes longer. 



The specimens measure from over 20 mm. long, 5- mm. wide near 

 the upper end, to about 8 mm. long, 1 mm. wide. 



BALANUS CRENATUS DELICATUS, new subspecies. 



Plate 42, figs. 3, 3a, 3&. 



. Cat, No. 18039, U.S.N.M., from a buoy on Ilumboldt Bar, 

 California, received from Leland Stanford Junior University; asso- 

 ciated with Balanus flos. 



The walls are thin, as in B. c. curviscutum; not ribbed; parietes 

 covered with a thin epidermis of very pale yellow tint; radii wide, 

 white. Parietal tubes square, rather numerous, 16 in the rostrum of 

 the type-specimen; septa very thin, not crenulated. No transverse 

 septa in the lower half of the tubes. 



