180 CAMPANTJLARIID.E. 



of the stem varied amongst the specimens which he suc- 

 ceeded in rearing ; in some cases it extended throughout, 

 in others it was confined to the top and bottom. In some 

 of the young zoophytes the ringing at the base ' ' was pre- 

 ceded by a slight dilatation ; " the denticulations on the 

 margin of the calycle were usually seven in number. The 

 mature trophosome has yet to be observed. 



Forbes gives the number of tentacles on the free zooid 



.at from 16 to 20; but he adds that between each pair 



there is a rudimentary marginal tubercle, which would no 



doubt be developed into a perfect tentacle. There may, 



perhaps, be a still further increase in number. 



Hub. Hebrides, common (Forbes) : Firth of Forth 

 (T. S. W.). 



Genus GONOTHYILEA, Allman. 



Der. y6vos, offspring, and Svpalos, outside the door. 

 LAOMEDEA, Lamouroux (in part). 



GENERIC CHARACTER. Stem erect and branched, rooted 

 by a thread-like stolon ; hydrothecte campanulate and hya- 

 line ; pohjpiteft ivith a prominent contractile proboscis ; re- 

 production by fixed medusiform sporosacs, which are fur- 

 nished with a circle of filiform tentacles, and, when mature, 

 become extracapsular, and are borne on the summit of the 

 gonotheca. 



THERE is nothing to distinguish this genus from Cam. 

 panularia or Obelia but the structure and history of the 

 sexual zooids, which exhibit some very interesting pecu- 

 liarities. They are medusiform, but never become free : 

 the generative products are developed as in an ordinary 

 sporosac; but before their liberation the gonophore is 



