496 REVISION OF THE AXINELLIDiE, ii., 



has since been described, that its true affinities were until 

 recently(13) unsuspected, while the propriety of maintaining a 

 separate genus for its reception has not hitherto been called into 

 question. Whitelegge, disregarding the evidence afforded by 

 the microscleres present, and attaching overmuch importance to 

 the echinate arrangement of some of the spicules composing the 

 skeletal fibres, ari'ived at the <;()nclusiou that Allanto]>ho7-a is 

 intermediate between Echiuodathriii and 0])Mitaspon(/ia; whereas 

 T, in my earlier remarks in reference to the genus(12), expressed 

 the opinifjn that, provisionally at least, it should be placed in 

 the Mycalinse, and suggested the possibility of its relationship 

 with <'r(imhe( = TetrmitheUa). Since then, as I more recently 

 have found occasion to remark(13), a second species possessing 

 microstrongyla as microscleres in addition to sigmata and tricho- 

 dragmata, has been described by Hentschel(15) under the name 

 Tylode.ama 7nicrostrongyIa, which in spiculation accords so closely 

 with Alhmtophora plicata as to leave no room foi' doubting the 

 close genetic affinit}' of the two, yet the skeleton of which con- 

 forms, or at any rate closely approximates, to a halichondroid 

 type. Hence it seems to follow that the essential feature to be 

 taken into account in deciding as to the proper systematic posi- 

 tion of these species is not, in either case, the precise configura- 

 tion of the skeleton, but rather the constitution thereof from the 

 point of view of the spicular elements composing it, both mega- 

 scleric and microscleric; and accordingly one is led to suspect 

 the probability of their relationship with such species as Biemna 

 raegalosiyma Heiitschel(15), and Biemna chileusis 'lhiele(42), the 

 spiculation of wliich is essentially the same as theirs except only 

 in this respect, namely, that instead of microstrongyla the micro- 

 scleres include spherulse, — and in which, furthermore, the skeletal 

 arrangement is of a somewhat intermediate type. In support of 

 this, there now comes to light a third species with microstrongyla 

 (and, significantly, with spherulse also), -described below as 

 Allantophora victoriana, — which forms a definite and absolute 

 connecting-link between A. plicata and SigmaxiaeUa rioca/yp- 

 toides Dendy, it being even questionable, indeed, whether both 

 it and the last-named should not be looked upon merely as 



