THE SESSILE BARNACLES. 



17 



In all species examined the rami of cirri iv, v, and vi are nearly 

 alike in length and armature. The segments in nearly every speci- 

 men examined have three pairs of spines on the anterior side, the 

 lower pair being very small, and usually there are two unequal spines 

 at the posterior distal angle of each segment. The chajtotaxy is so 

 similar that it is hardly necessary to figure cirri of the several species. 



FIG. 7. VERKUCA ALBA, MAXILLA (<z) AND MANDIBLE (6) OF SPECIMEN FIGURED IN PL. 2, FIGS. 1-lB. 



The relative length and number of segments of the cirri are given 



*-j o o 



in the following table, in all cases from individuals believed to be 

 adult. It is, of course, understood that young barnacles have cirri 

 of fewer segments than old ones. 



