HYDROID FAUNA OF THE BERMUDAS. 255 



Schizotricha tenella, Nutting, 1900, p. 80, pi. 4, figs. 4, 5. 

 Schizotricha tenella, Nutting, 1901, p. 365, fig. 70. 

 Plumularia alternata, Congdon, 1907, p. 484. 

 Plumularia alternata, Fraser, 1912, p. 381, fig. 48. 

 Schizotricha tenella, Fraser, 1912, p. 383, fig. 52. 

 Plumularia diaphana, Bedot, 1914, ]). 89, tab. 5, figs. 14-16. 

 Plumularia diaphana, Stechow, 1919, i). 114. 



Plumularia diaphana is rather common on floating Sargassura. 

 Branches were observed in a few cases, though the colonies are nearly 

 always unbranched. Stechow noticed that in many colonies the 

 proximal three or four hydrocladia were paired instead of alternate; 

 I find this to be almost universally the case in Bermuda specimens. 

 The gonosome is unknown. 



Plumularia corrugata Nutting. 



Nutting, 1900, p. 64, pi. 6, figs. 1-3. 



A few colonies, 10-12 mm. high, were found on floating Sargassum. 

 The gonosome was absent. The colonies were unbranched, and the 

 stem showed a pair of internal ridges at both the proximal and distal; 

 end of each internode. 



Plumularia inermis Nutting. 



Nutting, 1900, p. 62, pi. 5, figs. 1, 2, 2a. 

 Fraser, 1912, p. 382, fig. 50. 



This delicate hydroid covered thickly a large area of eel-grass in 

 the shallow water of Fairyland Creek; the colonies attained a height 

 of 18 mm. The trophosome agrees with Nutting's description, except 

 that the intermediate internodes are much more numerous than one 

 would infer from his reference to their "occasional appearance," and 

 there are often one or two short intermediate internodes between the 

 proximal hydrotheca and the stem. The hydrocladia rarely bear more 

 than three hydrothecae, and are often prolonged into stolons. 



The gonosome, heretofore unknown, was found in abundance. The 

 gonangia (Figs. 3, 4) are 20-30 times as long as the hydrothecae, unpro- 

 tected, oblong-ovate, decidedly annulated throughout, and differing 

 from those of all other American species of Plumularia in springing 

 directly from the hydrorhiza. The colonies are dioecious; the female 



