30 BULLETIN OF THE 



IV. Affinities of Urnatella. 



From the frequent opportunity that I have had successfully to com- 

 pare the organs of Urnatella, even in detail, with those of Pedicellina 

 and allied genera, there remains no doubt in my mind of its close rela- 

 tionship to those forms. Arthropodaria, especially in its segmentation 

 of the stem and the associated budding process, seems most closely to 

 resemble Urnatella. In three points of importance, however, Urnatella 

 differs from other Pedicellinidae, namely : (1) in the possession of a cloaca 

 (and absence of a brood-sac 1) ; (2) in the presence of water or excretory 

 canals in the stem and calyx, — which are so striking that they could 

 hardly have been overlooked if they occurred in other Pedicellinidse; 

 and (3) in the absence of the stoloniferous type of budding. 



As for the last difference, however, I have tried to show that there is 

 a stolon from which the individuals of the Urnatella stock arise, although 

 it is small. Whether this rudimentary condition of the stolon is an 

 ancestral or a degenerate character is doubtful ; 1 have been inclined to 

 consider it the latter. 



' In regard to the first dilBPerence, I must point out that in the male of 

 Arthropodaria there is a condition resembling that found in Urnatella, 

 for in the former genus (Foettinger, '87, Plate X. Fig. 8) the anus, vas 

 deferens, and excretory tubule open near together. 



The second difference concerns a very important set of organs, and if 

 they should be shown to be indeed absent in Arthropodaria Benedeni, it 

 ■would lead us to conclude that in one respect at least, perhaps owing to 

 physiological needs, Urnatella has retained a more ancestral condition 

 than its near allies. 



V. Affinities of the Bryozoa. 



There are three prevailing views concerning the relationship of the 

 Bryozoa to other groups. According to one view (most recently and 

 ably defended by Ehlers) they find their nearest allies in the Gephyrea ; 

 according to the second view, they have sprung from the'lower worms, — 

 from Rotifer-like ancestors. The third view (that of Hatschek) assumes 

 that Ectoprocta and Endoprocta are in fact not closely related, but that 

 the former should be placed near the Gephyrea, the latter close to the 

 Rot if era. 



The reasons for this difference of opinion are not far to seek. Those 

 •who have begun their studies with the Ectoprocta, particularly with 



