4 NATURAL HISTORY BULLETIN. 



Opercularella lacerata Johnston. Found growing 

 on young stems of Tubularia indivisa from Millbay rocks, on 

 April 26th. Other specimens were creeping over the stems 

 of Eudendrium. This is, I believe, the first recorded occur- 

 rence of the species at Plymouth. 



Opercularella hispida, n. sp 1 



This species bears some resemblance to Calycella syringa 

 Linn., from which it differs in having a much shorter pedicel, 

 a not strictly tubular hydrotheca, a greater number of seg- 

 ments to the operculum, in the absence of the tubular exten- 

 sion of the operculum, and in a much thinner structure, the 

 hydrotheca? being of glassy transparency in O. hispida but of 

 a decided brownish or yellowish horn colour in C. syringa. 

 The most striking feature, however, of the present species is 

 the remarkably hispid appearance of the tentacles, which 

 appear to be made up of series of triangular segments on 

 account of the formidable array of large nematocysts with 

 which they are armed. While examining the expanded ten- 

 tacles with a Y% objective, I was so fortunate as to see these 

 batteries of projectiles suddenly explode, sending out a per- 

 fect maze of barbed threads, which appeared to be larger and 

 longer than those of any hydroid that I have seen, except 

 Nematophorus grandis Clarke. 



In the absence of the gonosome, it is impossible to say with 

 any certainty to which genus this interesting little species 

 belongs. The general form of the hydrotheca, the cylindrical 

 hydranth with conical proboscis together with the convergent 

 teeth, give a facies like that of the genus Opercularella, in 

 which it is provisionally placed. 



Cadycella syringa Linn. Found growing abundantly 

 on young stems of Tubularia indivisa. The pedicels are 

 often much longer than one would judge from Hincks' figure. 

 The mass of root-stalks from this species running along in 

 approximately parallel lines on the host and giving off the 



1 A detailed description, with figures, will appear in the Ann. and Mag. 

 Nat. Hist. 



