4 Mr. J. J. Qaelch on some 



Family Zygophylacidse. 



Hjdrothecse continuous with, but not jointed to, a lateral 

 process of the stem ; paired nematophores or nematophore-like 

 bodies at the base of the hydrothecae, one nematophore being 

 on each side on the lateral process. 



Zygophylax, nov. gen. 



Hjdrocaulus erect, branched, composed of many tubes 

 aggregated together ; branches unjointed 5 hydrothecae bise- 

 rial, alternate, tubular, sessile, narrowed and constricted to- 

 wards the base, and continuous with a slightly enlarged lateral 

 projection of the stem. On the raised lateral edges of this 

 process are placed two small, elongated, tubular structures, 

 one on each' side at the base of the hydrothecee, which are 

 constricted and jointed towards their base, and which do not 

 appear to differ in any essential particular from the jointed, 

 stalked nematophores which are characteristic of so many of 

 the Plumulariidffi. 



Reproduction unknown. 



This genus is only known in the dry state ; and the charac- 

 ters of its hydrophyton relate it, on the one hand, to the 

 Lafoeidge, and on the other to the Haleciidse. It differs essen- 

 tially, however, from the forms included under those families, 

 and notably so in the possession of the paired nematophores 

 at the base of the hydrothecas — a character so striking and 

 constant as to justify, in my opinion, the formation of a new 

 family to receive it. 



Prof. Allman, in his Report on the Plumulariidse of the 

 ' Challenger ' expedition (p. 6) , has given an extremely 

 valuable note on our knowledge of the occurrence of nemato- 

 phores or nematophore-like bodies in Hydroids other than the 

 Plumulariidge, and it is interesting to note that such bodies 

 occur on forms allied or referable to Lafoea and Halecium. 

 The present form adds another to the list with much the same 

 relation, though the certainty of its position in classification, 

 based on the details of the structure of the complete hydro- 

 soma, must await the confirmation derivable from fresh or 

 well-preserved specimens. 



Zygophylax profunda, n. sp. (PL I. fig. 4.) 



Stem fascicled, erect, much branched j branches very thin, 

 springing immediately from beneath a hydrotheca, which 

 therefore becomes placed in the axil of the branch. Hydro- 

 thecEe very small, alternately placed at regular intervals, 

 short, tubular, and curved so as to look outwards and down- 

 wards, with two or three annulations generally well deve- 



