194 



BULLETIN 93^ UNITED STATES NATIONAL MUSEUM. 



the base, edges laminate, the lanihiie often someAvhat irregular, 

 branching, but not very distinctly denticulate. Aire broad, with 

 nearly horizontal sumniits. 



The basis is calcareous, thin, not porous, its inner face deej)ly 

 grooved radially, the periphery being denticulate, with deep pits 

 for the basal septa of the parietes. 



The labrum (fig. GOf ) usually has three teeth -on each side. 



The palpus (fig. QQa, c) has an irregular longitudinal row of 

 pectinated bristles on the labral face and two dense groups of spines 

 at the distal end. 



Mandible (fig. i'do) substantially as in B. crciuitus. 



Vu;. 00. — Balanus hesperius. Albatross station 34?l3, Beuing Sea. a, c, both sides oh" 



THE LABUUM AND OF ONE PALPUS. 1), 27Tn SEGMENT OH' CIRRUS VI. 



Maxilla (fig. 616, c) is slightly notched under the two great spines, 

 there are nine spines below the upper pair in the type, seven in 

 another specimen, one of them stouter, as in B. halanus. 



Cirri, first and second pairs injured in the type-specimen. The 

 posterior ramus of cirrus i has 9 or 10 segments; anterior segment 

 had been decidedly longer. Cirrus iii with the pedicel expanded as in 

 B. crenatus; posterior ramus of 12 segments two-thirds the length of 

 the anterior of 15 segments. The segments are densely bristly, with- 

 out any spinules or teeth. The posterior cirri have segments with 

 three or four pairs of spines, the lower pair minute; the posterior 



