THE SESSILE BARNACLES. 



177 



Tips of the terga and scnta diverge conspicuously, as in t,ypical 

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

 The articuhu' ridge is longer and more Avidely reflexcd than in the 

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

 is narrow. 



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

 illa about as in tj^Dical 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 fxat, multifid 

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

 cirri have 24 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. Avide near 

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



BALANUS CRENATUS DELICATUS, new subspecies. 



Plate 42, figs. 3, 3a, 35. 



Type.— Ci\t Xo. 18039, IT.S.N.M., from a buoy on Humboldt Bar, 

 California, received from Leland Stanford Junior University ; asso- 

 ciated with Balanus flos. 



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

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

 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. 



