MUSEUM OF COMPARATIVE ZOOLOGY. 79 



is further supported by the fact that, as a stolon may arise from the 

 Crjlinderzelle of Victorella, so iu Hypophorella such a conditiou is not 

 uncommon, although hardly typical. In accordance with this hypothesis 

 the formula for Hypophorella might be given thus : — 



(9) 



Ehlers ('76, pp. 127, 128), in founding the group of Stolonifera, clas- 

 sified the different methods of arrangement of the individuals in the 

 colony as follows : — 



I. Many polypides (Nahrthiere) on the single joints of the stolon 



(Stengelgliedei-ri). 



1. On the entire length of the joints, 

 (a.) Arranged in two rows. 



(b.) Arranged in a spiral, 

 (c") Arranged in one row. 



2. At the ends of the joints, 

 (a.) In rows. 



(b.) Massed. 



II. Only one polypide Ndhrthier on a joint of the stolon. 



1. Polypide lateral, near it one or many stolonic joints (Hypophorella). 



2. Polypide terminal. 



In the present state of our knowledge, it is very difficult to say how 

 the types of budding shown in those Stolonifera which possess more than 

 one Ndhrthier on a joint of the stolon are related to, or are to be connected 

 with, the types of Paludicella, Victorella, Hypophorella, or other genera 

 possessing only one Ndhrthier to a joint. This could doubtless be deter- 

 mined, however, by studying the early stages in the development of the 

 stocks. Taking them as they are, however, we find a very simple condi- 

 tion in the stocks of Class I., in which the Nahrthiere are arranged in a 

 single row, as in Vesiadaria spinosa (cf. Hincks, '80, Plate 73, Figs. 3-7). 

 The tip of the stolon consists, as I have myself observed in allied spe- 

 cies, of somewhat cubical cells of variable thickness, and it is from this 

 tip that the Anlagen of the individuals arise. Lateral branches occasion- 



