102 BULLETIN OF THE 
I have already stated (page 65) that the region from which the re- 
generating buds of Cheilostomes arise, although one of flattened epithe- 
lium, is one in which many more nuclei persist than elsewhere in the 
adult (cf. again Fig. 71). This fact, coupled with the constancy of 
position of regenerating buds with reference to the degenerated polypide, 
is to my mind evidence against the assertion that buds arise here from 
“histologically very definitely differentiated tissue.” 
As for regeneration in Endoprocta, no one is more competent to speak 
than Seeliger himself. I am the more surprised, therefore, to find that 
in Ascopodaria macropus, which is quite closely allied to the species 
studied by Seeliger (°89), the cells at the part of the stalk immediately 
below the ‘“ head,” from which regenerated buds arise, are, as Elhlers’s 
magnificent Pedicellina work shows, very large and cuboidal (Ehlers, 
90, Taf. II. Figs. 26-33). I think one may conclude that a similar 
condition obtains in some cases in Pedicellina, even judging from Seeli- 
ger’s own drawings, although they are drawn to a scale that is not quite 
large enough to allow of settling this point (Seeliger, ’89, Taf. X. Fig. 
35, a, Fig. 41, etc.). 
If the increase in size of the flattened cells, and their subsequent rapid 
division and invagination to form a bud, are due to their more active nour- 
ishment, it would be difficult to see why certain cells of any region should 
quickly undergo this modification, while the adjacent cells apparently 
as favorably situated with reference to the acquirement of food retain 
their flattened, quiescent condition, if we assumed such favorable situation 
to be the only requisite. Still less satisfactorily would such an assump- 
tion explain the regular position of regenerating buds. It is taking only 
one step farther back, but, to my mind,.a helpful step, to assert that cell 
proliferation in any region which produces invagination depends upon 
the capacity of the cells of that region to become better nourished than 
their fellows. This may evidently be effected by a diminution in the 
feeding capacity of the surrounding cells, or by an increase in this respect 
in the growing cells. 
IV. Relationships of Endoprocta and Ectoprocta. 
I discussed this topie in my earlier paper (Davenport, ’90, pp. 132, 
33). I have only to add, that later studies have confirmed my 
opinion of Nitsche’s correctness in placing these two groups close to- 
gether, and in regarding the Endoprocta as nearer the ancestral types. 
The stages of Figures 25 (Plate ILI.) and 77 (Plate IX.) probably rep- 
