138 NEW INVERTEBRATA FROM 



the outer wall of the stem in the interior. These muscular 

 blocks do not always correspond in dimensions with the 

 size of the separate nodes externally indicated by constric- 

 tions in the stem. 



What are the zoological affinities of Ascorhiza among 

 Bryozoa ? 



The character of the carnose capitulum, in which the 

 polypides are wholly drawn out of sight, recalls the genus 

 Alcyonidium. No known ctenostomatous genus has a 

 stalk like that of Ascorhiza and none of the genera allied 

 to Alcyonidium have this structure. 



From the entoproctous genera Pedicellina, Loxosoma 

 and Urnatella which have a pedunculated habit, Ascorhiza 

 differs in the character of the capitulum. We find a homo- 

 logue of this structure in the last mentioned genus, the 

 fresh-water Bryozoan described by Dr. Leidy. The ca- 

 pitulum is thought to be homologous with the " polyp-head" 

 of Urnatella, for if we suppose this structure to be greatly 

 enlarged and consolidated we have a structure almost iden- 

 tical with the capitulum. The stem of Urnatella, as so 

 beautifully figured by Leidy, resembles that of Ascorhiza 

 in many particulars. 



While, however, Ascorhiza differs from all known ento- 

 proctous Bryozoa in the colonial form of the capitulum, the 

 stem is found in several entoproctous genera, but nowhere 

 does the likeness appear to be so close as in the genus Ur- 

 natella. 



In Ascopodaria likewise we have, as figured in the re- 

 port on the " Challenger" Bryozoa by Busk, at the base 

 of a peduncle a barrel-shaped body which in some partic- 

 ulars resembles the jointed stem of Ascorhiza. This 

 structure in Ascopodaria forms a cup-shaped socket from 

 which the stem arises and which lies at the very base of 

 the peduncle. Other resemblances between the two genera 



