22 BULLETIN OF THE 



but the division, progressing towards the calyx, of an originally simple 

 stalk into a number of parts, — that the growth of the Urnatella stalk 

 is limited just as that of the Pedicellina stock is limited, and for the 

 same reason. 



3. Orientation of the Individuals. 



The orientation of the individuals of the stock seems to be here, as in 

 Ectoprocta, a very definite one. In Pedicellina and its close allies, as 

 well as in Urnatella, the young individuals budded from the parent 

 stalk face the same way as the polypide of the parent stock. Seeliger 

 ('90, p. 571) has pointed out that in all the species of Loxosoma the 

 orientation of the buds with reference to the parent is definite, but 

 different from that found in Pedicellina. The orientation of the buds in 

 Loxosoma (which arise, as in Pedicellina, on the oral side of the mother) 

 is the reverse of that of the mother. Thus it comes about that the 

 oral aspect of the buds in the Pedicellinidse is turned towards the pe- 

 riphery of the stock, that of Loxosoma towards the centre. This is 

 the same difference which has been found to prevail between the buds 

 ofPhylactolaemata and Gymnolsemata, and as in this case, so in Endo- 

 procta the differences may be harmonized by a different method of ex- 

 pression. In all Endoprocta the oral aspect of the buds is turned toivards 

 the centre of proliferation. For in Loxosoma new individuals are pro- 

 duced between the next older and the parent stock, the centre of prolif- 

 eration remaining in the parent stock, while in Pedicellina it migrates 

 away upon the end of the stolon. The typical condition in Loxosoma is 

 represented by the formula 



a b c d * A; 

 that of Pedicellina by 



* d c b a A, 



in which the asterisks represent gemmiparous tissue. 



The general statement of the relation of the aspects of the buds to the 

 proliferating region is the reverse of that which I have given for Ecto- 

 procta ('91, p. 82), which reads, "In both Phylactoleemata and Gymno- 

 Ifemata, the anal aspect is turned towards the gemmiparous region." 

 It is important to note, however, that this difference corresponds to a 

 difference in respect to the part of the alimentary tract which is formed 

 by the principal pocket of the atrium, for this in Ectoprocta gives rise 

 to the posterior part of the elementary tract ; in Endoprocta, on the con- 

 trary, to the anterior part. The differences in the process of budding in 



