65S REVISION OF THE AXINELLID^, iii., 



extremely probable, however, that the acanthoxea of these genei'a, 

 like those undoubtedly of the recently described genus Acanthoxa 

 Hentschel(l6), are homologous with the acanthoscleres of the 

 Myxillina?, and that the correct place of Hiyyiiisia and Halic- 

 iieniia is, therefore, in the family Desmacidonidse. 



The genus is represented on the Australian coast by two 

 varieties of H. coraUoides, — viz., maxsa/is Carter and scnbra 

 Whitelegge, — re-descriptions of which are given below. The 

 other named varieties of this species (the typical form of which 

 comes from the West Indies) are Higgin's(17) var. hberiensis 

 from Cape Palmas and var. arcunta from Ireland; while the form 

 recorded by Topsent(48) from Amboina as //. coraUoides var. 

 massalis probably constitutes a fifth variety. Carter's H. coraU- 

 oides var. natalens's, although possessing the external habit char- 

 acteristic of //. coraUoides, is distinguished by having the 

 skeletal fibi'cs composed of stylote instead of oxeote megascleres, 

 and may, therefore, conveniently be regarded as specifically 

 distinct. 



To supplement the brief diagnosis of //. coraUoides given 

 above, and at the same time to indicate the main points of difi'er- 

 ence distinguishing the varieties massalis and scnbra from the 

 remaining forms of the species, the chief characters of the latter 

 (excepting Topsent's var. massalix, the description of which I have 

 not seen), may be summarised as follows: — 



//. mass(dis (typical form). .Stipitate, fiabelliform; "consisting 

 of lobate compressed branches of irregular and luxuriant growth, 

 united clathrously ur continuously; surface deeply furrowed in a 

 vertical direction, the ridges between the furrows being narrow 

 and, in the young growths, serrated witli tooth-like projections, 

 passing in the older portions into rounded or tubercled pro- 

 minences." The skeleton is "a spiculiferous network of lozenge- 

 shaped reticulation," consisting (in part) of plumose fibres, the 

 spicules of which are not enclosed in spongin, but merely 

 cemented together by it where they touch or cross each other. 

 The megascleres (oxea) appear to be of two kinds, — those of the 

 fibres more or less curved and attaining a maximum size of 635 



