62 S. F. Clark on New and Rare Species of Hydroids. 



times attaining a considerable length. Hydrothecae largest in the 

 middle, tapering very slightly toward the base, rapidly converging at 

 the distal end, and supported on short annulated pedicels, consisting 

 of three to five rings. Gonothecje fusiform, with the tapering neck 

 often somewhat elongated ; length about twice that of the hydro- 

 thecffi. They contain one to three small globular or ovate immature 

 raedusoids. The pedicels consist of three to six annulations. In the 

 creeping form the hydrothecre appear at intervals borne on short 

 ringed stalks consisting of about three to six rings. 



Portland, Maine, August, 1873, with gonothecae, on piles of wharves; 

 off Montauk Pt., Long Island, 5-15 fathoms, August, 1874, — U. S. 

 Fish Commission. 



This species closely resembles O. lacerata of Hincks, from which it 

 is distinguished by the forms both of the hydrotheca? and gonothecae. 

 The hydrothecae are also smaller than those of 0. lacerata. As the 

 reproduction has not been traced in this species, it can only be refer- 

 red to the genus provisionally. I am inclined to think, from the 

 shape of the gonothecte and from the fact that they often contain 

 two or three distinct reproductive bodies, that it may not belong 

 under Opercularella. 



Opercularella lacerata Hincks. 



Campanularia lacerata Johnston, Brit. Zooph., p. Ill, PI. xsviii, fig. 3. 

 Opercularella lacerata Hincks, Brit. Hydr. Zoopli., p. 194, PI. xxxix, fig. I. 



Plate IX, fig. 6. 



Stem erect, simple, slightly flexuous, more or less annulated through- 

 out, sparingly branched ; branches short undivided. Hydrothecae 

 ovato-fusiform and borne on short pedicels of but two or three annula- 

 tions; operculum composed of six to eight segments. Gonothecae, 

 of the female colonies, a trifle wider at the distal end, and tapering 

 very slightly toward the base, supported on short ringed pedicels ; 

 the medusoid (sporosac) containing the planuhi? is quite large, the 

 diameter being about equal to the length of the gonotheca ; from 

 two to five planulfe in each medusoid. 



New Haven, Conn., on piles of Long Wharf, May 13th, 1875, with 

 extracapsular medustB. — S. F. Clark. 



The hydrothecae in this species average about one tliird larger than 

 those of 0. pumila ; the segments of the opercula are more deeply 

 cleft ; and there are differences in the form of the gonothecae. 



