BRITISH ZOOPHYTES. 326 



lateral^ near wide extremity of eacli cell. LopliojpJiore 

 orbicular. No epistome or calyx. — Allman. 



1. P. Ehkenbeegii, Van Beneden. Plate XXIV. 

 figs. 5, 6. 



Alcyoiiella articulata {Ehrenherg), A. diaphana 

 {Nordmann, Wrigman), P. articulata {Gervais, Van Ben., 

 G. J., D. L., Allman), P. procumbens {Hancoch, Aid.). 



Hab. : Widely distributed in canals and lakes. 



This is tbe only fresh- water species known of the 

 Gymnol^emata. 



" Of all the genera of fresh-water polyzoa this is the 

 easiest to distinguish ; but it is the most difficult to 

 discover. The naturalist who is occupied with the 

 study of these lower animals may have it under his 

 eyes for some time without knowing it, as the tubes 

 are so slender, and the colony bears so strong a re- 

 semblance to a plant, that he would not dream of 

 examining it." — Van Beneden. 



The polypes have 16 tentacles, and are lodged in 

 cells separated by distinct septa. The mode of growth 

 is stiff. The colony is trichotomously branched, and 

 the branches project almost at right angles from the 

 stem. The orifice is on the side of the cell near the 

 top. The cell itself is elongate and claviform. 



Order II. PKYLACTOL^MATA. (Lophopea.) 



Zophophore bilateral ; moidli with an epistome. Arms 

 of lophophore free or obsolete. 



FAMILY I. CRISTATELLID^. 

 Goenoecium free, locomotive. 



