Hydroida from Deep Water. 129 



the genus Plurmdaria^ and a very beautiful new generic form 

 {Poly2)luinaria) allied to the latter. 



Heteropyxis norvegica^ n. sp. 



Amongst the new Plumulariidai we find a form which is 

 referred to the Heteropyxis of Heller. I have given reasons 

 elsewhere * for merging this genus in Plumularia ; but I now 

 find that I have misapprehended the characters on which it is 

 based. In his brief generic diagnosis Heller makes no mention 

 of the only peculiarity to which I should be at all disposed to 

 attach any importance ; and as I was unacquainted at the time 

 with Meneghini's description of his Loioenia (which is identical 

 with Heteropyxis)^ my decision was founded on an imperfect 

 knowledge of the distinctive characters. The real peculiarity 

 of the genus Heteropyxis is the subspiral arrangement of the 

 pinna? ; in this it differs from Plumularia and makes an ap- 

 proach to Antenmdaria. The other characters are insignificant ; 

 but it may be convenient to retain the genus for those forms 

 which, without being truly verticillate, have the pinnse distri- 

 buted round the stem. The curious point about H. norvegica 

 is that it bears cornucopia-shaped capsules, exactly resembling 

 those oi Plumularia cornu-copice [va\h\)^ a species from the 

 Devonshire coast ; the form is remarkable, and it is, as far as 

 I can judge, absolutely identical in both. In H. norvegica, 

 however, the position of the gonothecee is peculiar : they are 

 developed in pairs from a distinct process on the lowest joint 

 of the pinna, a little above its point of oiigin. 



Dipthasia elegans, n. sp., and Sertularia tenera, n. sp. 



These two new Sertularians were obtained from a bottom 

 of soft mud or ooze, in depths ranging from 150 to 200 fathoms, 

 and, we may therefore presume, in a comparatively warm 

 area. 



The Diphasia bears a strong general resemblance to D. at- 

 tenuata (mihi). The chief points of difference seem to be the 

 absence of joints on both stem and branches and of the tendril- 

 like prolongations of the latter, the greater distance between 

 the pairs of calycles, and the extraordinary development of the 

 creeping stolon. The latter is the most marked character, and 

 connects itself directly with the nature of the locality in which 

 the species is found. A luxuriantly developed, much ramified, 

 and sinuous fibre spreads over the muddy sea-bottom, through 

 a great part of its length perfectly free, and only attached 

 here and there to the small fragments of stone or shell sparingly 



* " Notes on Prof. Heller's ' Catalogue of the Ilydroida of the Adriatic' ' 

 (Ann. & Mag. Nat. Ili.st. ser. 4, vol. ix. p. 119). " 



