CONGDON. — THE HYDROIDS OF BERMUDA. 



471 



Trophosome. Colonies twelve to eighteen millimeters long, the small 

 diameter of the stem and the hyalinity of the perisarc giving the ap- 

 pearance of fragility. Short, strongly marked nodes, ending below 

 with an abrupt curve and attached to the side of the next lower node ; 

 ending above, apparently in the pedicel of a hydranth. Stem genicu- 

 late, somewhat curved in each node. Hy- 

 dranths alternate. The branches, which 

 arise from the growth of a pedicel, given 

 off irregularly, duplicating the structure 

 of the stem. Annulation at lower end of 

 node, sometimes extending well up or oc- 

 curring midway in its length (Figure 18). 



Ilydrothecae campanulate, elongated, 

 with nearly straight sides, tapering most ab- 

 ruptly close to pedicels. Rim with twelve 

 to fourteen pointed teeth separated by 

 rounded edges. In old individuals the 

 walls often folding and cracking longitudi- 

 nally, causing the hydrothecae to collapse ; 

 the teeth in part breaking off, producing 

 an irregular edge. Diaphragm with a small 

 opening sometimes quite far from base of 

 hydranth. Pedicels often as long as a 

 node. If entirely annulated there are 

 from ten to twenty rings. 



Gonosome. Gonothecae attached closely 

 to base of a hydranth pedicel, or carried 

 away from the stem by its elongation, 

 nearly twice as long as hydrothecae, flat- 

 tened, ovoid, truncate above, with a flaring 

 ring and tapering to the short annulated 

 pedicel. There may be some suggestion 

 of annulation on the wavy surface. About 

 six medusa buds can be found on the 

 blastostyle. Their bells are deep and their 

 manubria large. The presence of four 

 tentacles indicates the genus Clytia. 



Figure 13. Clytia fragilis. 

 Half of a colony bearing a 

 gonotheca (X 18). 



Clytia simplex (new species). Figures 14, 15. 



This hydroid is only a little less abundant on Sargassum than 

 Aglaophenla minuta. It grows on some of the larger Bermuda 

 hydroids. 



