640 REVISION OF THE AXlNELLID^, ill., 



the otlier species might seem debatable. Owing to the kindness 

 of Prof. Dendy, I have had the opportunity, however, of examin- 

 ing a section of his Thrhtacophora nydricifurmis; and the close 

 resemblance in skeletal pattern, which I find to exist between it 

 and the species in question, leaves no doubt in my mind as to 

 their veiy near relationship. In these two species, interstitial 

 megascleres occur which are different from those composing the 

 fibres; but whereas in D. dathriformu tliey ai'e very scarce, and 

 are connected with the fibre-forming megasclei'es by intermediate 

 forms, such is not the case in the type-species. In D. durissima, 

 apparently, special interstitial megascleres either have never been 

 developed, or have become lost. 



Dragmatella, gen.nov. 



Dpfinition. — Axinellida3 of massive habit, provided witli digiti- 

 form tapering processes. Internal structure cavernous. Main 

 skeleton consisting of well-developed, non-plumose(l), multispicular 

 fibres ari'anged more or less dendritically. A dermal skeleton is 

 typically present, formed of tangentially-disposed megascleres 

 crossing in every direction. The megascleres are styli of a single 

 kind. The microscleres are trichodragmata alone, or accompanied 

 by trichites singly scattered. 



Type-species, D. abcrrans Topsent(46). 



To define the genus Biemna in such a way as to secure the 

 inclusion in it of Topsent's Desmticella aberrans, and at the same 

 time to exclude therefrom certain other species likewise possess- 

 ing trichodragmata alone as microscleres, — such, for example, as 

 those belonging to the genera Draymacidvn and Rhaphoxya, — is 

 extremely difficult, if not impossible; and, on that account, the 

 erection of a new genus for this species seems necessary. Even 

 apart from any consideration of expediency, however, it is doubt- 

 ful if the species could have been allowed to remain in Biemna, 

 — since, in addition to being without sigmata, it differs from all 

 strictly acceptable species of that genus in at least one other 

 noteworthy respect, namely, the possession of a dermal skeleton 

 composed of megascleres directed horizontally. 



