92 SIDNEY F. HARMER. 



possible in T, liliacea to see it by inclining the colony in a 

 suitable direction. The ooeciopore typically opens hori- 

 zontally ; or, in other words, its plane is vertical to the upper 

 or exposed surface of the ovicell. The edge of the ooeciopore 

 may be slightly everted, so as to form a narrow brim, or there 

 may be no eversion ; and the upper lip may be horizontal and 

 more prolonged than the lower lip. 



In all cases the ooeciopore is relatively large^ varying from 

 230 /u to 270 fx, that of an ordinary zooecium being 145 jul to 

 190 fx. When the structure is placed in a suitable position it 

 is possible to see some way down the tube of the ooeciostome 

 (fig. 7). This cannot be done in T. phalangea. 



The tube is moderately long, and is recumbent on a zooecium 

 or series of zooecia. It may occur on the proximal side of the 

 series, and look towards the oldest part of the colony, or it 

 may be placed on the distal side and look towards the growing 

 edge. 



T. liliacea is very common on certain Hydroids, parti- 

 cularly on Hydrallmania falcata, a fact familiar to many 

 of the older naturalists, and on Sertularella. It is easily 

 obtained from the masses of Hydroids brought up by trawlers 

 in water of twenty fathoms or more. The form of the entire 

 colony varies a good deal. It may remain closely attached to 

 the narrow stem of the Hydroid, its basal lamina curving 

 round the stem and thus giving rise to very irregular colonies ; 

 or it may remain attached merely by a small central area, and 

 grow out into free, erect branches, as in the var. radiata of 

 Hincks. In this condition it assumes a typical Idmonea- 

 form, having a very strongly marked alternate arrangement of 

 connate plates of zooecia. 



In a particularly fine specimen of this form, from the 

 Troudhjem Fjord, which I owe to the kindness of Dr. Nord- 

 gaard, a single series consists in some cases of as many as 

 eight zooecia, the inner ones being very much taller than the 

 outer ones. The tip of the longest branch is about 11 mm. 

 from the centre of the colony. The ooeciostome belonging to 

 this branch is on the distal side of the seventh series (of one 



