THE SESSILE BAENACLES. 



195 



distal aiiijle of each segment has a gi'onp of spines at least as long as 

 the segment; both rami of cirrus vi have 34 segments (fig. 006). 



The penis is longer than the cirri, with ver}'- 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 when it is 3 or -l mm. in diameter, sometimes later, np to 

 7 mm. The tjY>Q 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 o'eimtus^ B. halanokh's, and rarel}^ B. glnndula. The small 



Fig. G1. — Balanus hespkrius, station 348.'>. a, mandible, 'b, maxilla, c, imaxilla oij' 



SPECIMEN FROM RT.\TION 3540. d , P.. H. NIPPONENSIS, MANDIBLE. 



number of spines on the posterior cirri distinguishes B. liesperlus 

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

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

 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 40, 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. INIandible 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. 



