MALE. 191 



lxient, which is considerable only when the lower part 

 of the peduncle is almost parallel to the coats of the sack, 

 seems caused by the growth and repeated exuviations 

 of the female ; I believe, that the larva attaches itself 

 to the chitine tunic of the sack, and that the cement, by 

 some unknown means, affects the underlying corium, so 

 that this particular portion of the tunic is not moulted 

 with the adjoining integuments, and that the growth of 

 the surrounding parts subsequently causes this portion 

 to be buried deeper and deeper : it is, I believe, in the 

 same way as the end of the peduncle in Con c7io derma 

 aurita, sometimes becomes imbedded in the skin of the 

 whale to which it is attached. 



The outer tunic of the peduncle is thin and structure- 

 less : in the fold (fig. 1 h) under the cirri, there is a central 

 triangular gusset of still thinner membrane, corresponding 

 in position to the membrane connecting the two terga in 

 the female, and there subjected to much movement. 1 

 may here remark, that this fold, in its office of slightly pro- 

 tecting the thorax and in its position, evidently represents 

 the capitulum with its valves, enclosing the whole body 

 of the female. The outer tunic is lined by corium, mot- 

 tled with purple, and within this there are two layers of 

 striae-less muscles, transverse and longitudinal, as in all 

 pedunculated Cirripecles. The corium extends some way 

 into the imbedded portion of the peduncle, and conse- 

 quently, the outer tunic there continues to be added to 

 layer under layer, and as it cannot be periodically moulted, 

 it becomes much thicker than in the upper free part of 

 the animal : the corium, however, does not extend to the 

 extreme point, so that in it growth of all kind ceases. 



Antennce. — The peduncle terminates (PI. V, fig. 1 e) 

 in the two usual, larval, prehensile antennae, which it is 

 very difficult to see distinctly; they are tolerably well 

 represented in fig. 5, greatly magnified. Their extreme 

 length, measured from the basal articulation to the tip 

 of the hoof-like disc, is ^ths of an inch, the disc itself 

 being ^ths of an inch. The disc is slightly narrower 



