132 
SIDNEY F. HARMED 
the two individuals formed by the fission. In the case of the 
proximal individual, the entire lophophore has to be formed 
de novo from a region which is far removed from the 
original lophophore. In the distal individual, regeneration 
if it takes place, presupposes the loss of the original lopho- 
phore. This latter process is of the same nature as that 
which has been described in other species, where the lopho- 
phore is thrown off, the wound closes, and a new crown of 
tentacles is formed from the extreme distal end of the animal* 
Many of the specimens figured illustrate the regeneration 
of the lophophore at the distal end ; and where the relations- 
of the tube give no indication of the previous occurrence of 
fission in this region (cf . section (c)) the regenerating lopho- 
phore appears to be a replacement of the original lophophore.. 
But as none of the regenerating specimens figured are as 
long as the fully adult specimen shown in PI. 7, fig. 2, it 
may be considered probable that they are all fractional 
portions of individuals produced by the metamorphosis of 
larvae. Neglecting for the moment the differences in the 
length of the individuals, the regeneration of the distal end 
may be illustrated by the following cases : 
In the distal individual shown in PI. 9, fig. 32, the thick- 
walled muscular region of the body is clearly indicated, with 
the collar-like partial invagination ( inv .) characteristic of the 
proximal end of this part. The new lophophore is repre- 
sented merely by the thickened body-wall at the extreme- 
distal end. 
In PI. 9, fig. 36, the distal thickening indicating the new 
lophophore is more distinct, and is separated by a slight 
annular constriction from the beginning of the muscular part 
of the body-wall. 
In PI. 8, fig. 13, the lophophore is still more distinct and 
shows distal lobulations which will become the new 
tentacles. 
Further stages in the growth of the tentacles are shown in 
PI. 8, fig. 11, and PI. 7, figs. 5, 4, and 8 ; and in the last of these- 
the formation of the new lophophore is practically complete. 
