94 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



more frequently on zoophytes than polyzoa, and 

 especially on Diphasia pumila. 



Order V. — Cladophorace^e. 

 Urospora penicilliformis, Aresch. 



{Conferva youngana, Eeport I.) 

 Puffin I. !, Anglesea ! 

 U. flacca, Holm, et Batt. 



(Ulothrix flacca, Eeport I.) 



I. of Man, Anglesea, Puffin I. ! 

 U. bangioides, Holm, et Batt. 

 Puffin I. !, Anglesea ! 



I found this form growing in considerable quantity at 

 the situations named, in the spring of 1890, and thinking 

 at the time that I had found the rare species Urospora 

 collabens, I made a careful study of its structure and life 

 history. Through the kindness of Professor E. P. Wright 

 I was enabled to compare my plant with the type specimen 

 of U. collabens in the Harveyan Herbarium at Dublin, 

 with the result that my plant proved to be not that 

 species but Urospora bangioides. I publish, however, my 

 observations on the species, although in doing so I in 

 great measure repeat Areschoug's work* on the allied U. 

 pencilliformis. The filaments vary greatly in length ac- 

 cording to age, an average fall grown frond being 6 — 10 

 cm. long. The frond is unbranched and tapers to base 

 and apex. Narrower regions also occur in the course of 

 its length. The base is an irregular disc formed by the 

 terminal cell, and frequently two or more cells above the 

 terminal cell. The cell wall is markedly two layered. 

 Cell division is usually regular, but frequently irregular. 

 I have found that this oblique mode of division is asso- 

 ciated with a peculiar method of vegetative multiplication. 



* Observationes Phycologicm, Pt. I. 



