THE SESSILE BARNACLES. 



195 



distal angle of each segment has a group of spines at least as long as 

 the segment; both rami of cirrus vi have 34 segments (fig. GOZ>). 



The penis is longer than the cirri, with very few hairs, and so far 

 as I can see, no point at its dorsal base. 



Examples from other lots examined vary in the armature of the 

 labrum and maxilla, and relative length of the rami of cirrus i, but 

 all are practically alike in other respects. 



As in other ribbed species, the early stages are smooth; the ribs 

 appear Avhen it is 3 or 4 mm. in diameter, sometimes later, up to 

 7 mm. The type is one of a very strongly ribbed lot. The ribs are 

 not quite so deeply cut in most lots, and they vary, as in all ribbed 

 Balani. It seems never to become elongated, club shaped, or columnar, 

 as in B crenatius, B. balanoides, and rarely B. glandula. The small 



FIG. 61. BALANBS HESPEUIUS, STATION 3483. a, MANDIBLE. &., MAXILLA, c, MAXILLA OF 



SPECIMEN FROM STATION 3540. d, B. H. NIPPONENSIS, MANDIBLE. 



number of spines on the posterior cirri distinguishes B. hesperius 

 from all of these species. B. glandula occasionally has almost or 

 quite poreless parietes, but the scutum is unlike that of B. hesperius. 

 It is almost exclusively seated on shells, especially gastropods, in 

 the collections at hand, but this may be because stones are less likely 

 to be taken by the collector. 



Plate 49, figure 8, represents a large typical specimen growing on 

 the anterior part of a Chrysodomus. Diameter 18 mm. This seems 

 to be the maximum size. 



In specimens from Albatross station 3540 the wall resembles that 

 shown in plate 49, figure 3. The labrum has one tooth on one side, 

 three on the other. Mandible and maxilla about as in the specimen 

 dissected from Station 5003, except that there is no notch below the 

 upper pair of spines of the maxilla. Cirrus i has 12 and 8 segments, 



