Length of calyx . 

 Length of narrovv 



part of stalk . . 

 Length of basal 



part of stalk . . 

 Total length . . . 



It will be seen that some of these measurements are variable, the size of the calyx, 

 however, depending on its age ; and the dimensions of the basal muscular part of the stalk 

 probably depending on its state of contraction. The Japanese specimens have, moreover, the 

 appearance of being less contracted than those obtained by the 'Siboga'. But there can be no 

 question that the narrow part of the stalk is very variable in length ; the cuticle being so thick 

 that the question of contraction need not be considered. The variability in length appears, 

 however, to be mainly the result of differences in growth. The individuals near the growing 

 points have short stalks ; and it is clear, from a comparison of these with older specimens, 

 that growth continues for a long time in the neighbourhood of the calyx, where the cuticle 

 disappears. Oka has called attention to the fact that the calyces are deciduous and are readily 

 regenerated ; a property which this species shares with other Pedicellinidae : — for instance 

 Pedicellina cernua l ). In the Japanese specimens I find that this process may be associated with 

 an increase in the length of the stalk, a distinct annular mark being visible at the junction of 

 the old and of the regenerated portions. The part thus added is very variable in length, but 

 it may be as long as the original stalk. Sometimes tvvo or even three annular marks are 

 visible, indicating as many successive regenerations. In the specimen figured (fig. 9) there is 

 some alteration of the cuticle near the middle of the stalk, suggesting that a joint might have 

 been formed later here ; and in another specimen a joint, with indications of the development 

 of longitudinal muscles, has actually been formed in a corresponding region. Specimens of B. 

 discreta with a jointed stalk have been figured by Waters (1904, PI. VII, figs 6a, 6d), 



The peculiar pores of the thinner part of the stalk traverse the inner layer of the cuticle, 

 but are closed by an external layer which, according to Oka, differs from the inner stratum 

 by staining with eosin. The position of the pore is sometimes, but not always, indicated by a 

 very slight convexity of the outer surface of the stalk. The basal, muscular portion of the stalk 

 is usually not separated from the thinner part by a diaphragm, although some of the Japanese 

 specimens show an annular thickening of the chitin, projecting slightly into the cavity of the 

 stalk, in that position. In one of the 'Siboga' specimens (337.1) the diaphragm is well developed, 

 and the longitudinal muscles of the basal thickening of the stalk are inserted into it. 



The stolon is composed of alternating segments, divided from one another by discoidal 

 diaphragms perforated at the middle. Each alternate segment gives off a stalk, the intervening 

 segments being barren. This arrangement may be considered typical in the Pedicellinidae and 

 has been correctly described by Oka for the present species. A lateral branch of the stolon is 



1) Cf. my paper on that species in Quart. J. Mier. Sci., XXVII, 1887, p. 256. 



31 



