148 NOTES ON PLYMOUTH HYDROIDS. 



the hydrautli is expanded, thus differing from most of the Cam- 

 panularidcc. 



GONOTHYR/EA LOVENI, Allman. This is one of the most abundant 

 species at Plymouth. A number of specimens of the genus that were 

 brought in from time to time during April and May differed so 

 materially from G. lovhii, and agreed so closely with the descriptions 

 of G. hyalina, Hincks, that I regarded them as belonging to the latter 

 species, and had so labelled them, when another batch of specimens was 

 brought in which showed completely intergrading forms joining the 

 typical G. loveni with almost typical G. hyalina. There is a strong 

 probal)ility that these two so-called species are but varieties of one 

 form, which should bear the name of G. lovhii, Allman. 



Opekcularella 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 occurrence of the species at Plymouth. 



Opercularella hispida, n, sp.* 



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 segments to the operculum, in the 

 absence of the tubular extension of the operculum, and in a much 

 thinner structure, the hydrothecfe being of glassy transparency in 

 0. 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 formid- 

 able array of large nematocysts with which they are armed. While 

 examining the expanded tentacles with a i objective, I was so fortunate 

 as to see these batteries of projectiles suddenly explode, sending out a 

 perfect maze of barbed threads, which appeared to be larger and longer 

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

 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. 



Calycella 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 peduncled hydrothecte, afford a good idea of how the 



* A detailed description, with figures, will appear in the Ann.' and Mag. Nat, Hist. 



