370 Mr. H. J. Carter on the Hexactinellidge. 



veil formed of the overlapping arms of a small spiniferous sex- 

 radiate spicule, whose outer vertical arm being undeveloped 

 renders it nail-like by the corresponding one projecting in- 

 ward like those just mentioned in Askonema. It is charged 

 also with rosettes of two kinds, one of which is the pappus- 

 like or pappiform one with straight capitate rays, as yet only 

 noticed in two other species, viz. Dactylocalyx subglobosa and 

 Holtenia Pourtalesii, Sdt. 



The details figured by Schmidt of Holtenia Pourtalesii (I. c.) 

 seem to me to ally it much more nearly to Rossella than to 

 Holtenia Carpenteri, the type species of the Holtenice, since 

 the former has not the birotulate spicule which is characteristic 

 of Holtenia and its associates. The pappus-like rosette last 

 mentioned is also characteristic of Holtenia Pourtalesii ; but 

 there is no rosette (at all events of this kind) in Holtenia Car- 

 penteri, &c. Again the large nail-like spicule of the surface 

 (I. c. Taf. i. fig. 4) is spined like that of Rossella antarctica. 

 Lastly, if the pappiform rosette with straight capitate rays be 

 equally characteristic of Crateromorpha, the latter also has 

 many points of resemblance in its structure to Rossella with 

 the rectangular lattice-like dermal veil &c, well seen in Rossella 

 velata, Wy. Thomson. 



Then the distinguishing character of Rossella is, that all its 

 anchoring-spicules are smooth, and all armed with four robust 

 recurved spines opposite ('Annals,' I.e.). It is also covered 

 (that is, R. velata and R. philippinensis) with the rectangular 

 lattice-like veil mentioned ; and besides the common forms of 

 rosette, it is charged with the pappus-like or pappiform one 

 with multitudinous flexed rays of unequal length without heads, 

 and arranged en fleur-de-lis, seen only in one other species, viz. 

 Sympagella mix. 



The arms of the large nail-like spicules of Rossella antarctica 

 are covered by a layer of microspines, with here and there large 

 curved spines, inclined outwards (' Annals,' I.e.). 



Habrodictyon speciosum and H. corbicula=Alcyoncellum spe- 

 ciosum and A. corbicula have been noticed under Euplectella 

 aspergillum. They are inserted here on account of their 

 spicular structure being enveloped in amorphous sarcode instead 

 of vitreous, fibre. If the glassy fibre be considered of no spe- 

 cific value, then they can be removed back to Euplectella asper- 

 gillum at any time. 



Hyalonema, from its twisted cord-like stem, composed of 

 long anchoring-spicules, passing through the head (Carteria, 

 Gray) so as to appear in a conical projection on the summit of 

 the latter, whereby the central portion of the sponge, which 

 thus hangs upon it, is rendered solid (instead of hollow, like 



