346 THE VOYAGE OF H.M.S. CHALLENGER. 



radiating irregularly from the centre towards the circumference. Surface even. Oscula, 

 pores and expansile dermal system unknown. Skeleton fibre stout, more or less furnished 

 with scattered warty tubercles. Auxiliary fibres abundantly tuberculated, terminating 

 spinulately. Insterstitial spicula rectangulated, hexradiate, large ; radii nearly equid, 

 attenuated and acutely terminated. Retentive spicula spinulo-quadrifurcate hexradiate 

 stellate ; terminal radii long." 



The fifth form, Iphiteon callocyathes = Myliusia callocyathes, Gray, belongs to 

 another genus, Myliusia, Gray, which will be described more closely below. 



Oscar Schmidt ^ first called attention to the fact that the greater number of the forms 

 described by Bowerbank as Dactylocalyx are not Hexactinellids at all, but belong to the 

 Lithistida. According to Oscar Schmidt, the genus Dactylocalyx strictly embraces those 

 sponges which are characterised by a triaxial type of spicule, " their siliceous network 

 resembles neither the wide tubes of Farrea nor the prismatic tissues of A2?hrocallistes, 

 but a more dense irregular tresswork. The habit of the body may accordingly be very 

 variable." 



In addition to the meshed forms, Dactylocalyx pumiceus and Dactylocalyx suhglo- 

 bosus, Oscar Schmidt described and figured a third species, of very different appearance, 

 under the designation Dactylocalyx crisiyus. From a short compact solid base, there 

 rises a simple or divided funnel-shaped tube with a thin and somewhat folded wall, while 

 the upper terminal opening appears to be either irregularly round or else sinuous and 

 fissure like. Short tube-like lateral protuberances or branches which are here and there 

 arranged in distinct longitudinal rows open to the exterior by a rounded aperture. 



In an article on the classification of the sponges, published in 1872,- Gray distinctly 

 curtailed his family of the Dactylocalycidae as established in 1867. He removed the 

 genus Macandreiuia, which was regarded as representative of a special family, the 

 Macandrewiadse, retained the genera Daxitylocalyx, Myliusia, Kaliapsis, and Disco- 

 dermia, and characterised the restricted family as follows : — " Sponge massive or ex- 

 panded or cup-shaped. Skeleton more or less regularly reticulated, with angular 

 openings diverging from the centre." 



In 1873 Carter^ united Dactylocalyx pumiceus, Stutchbury, Daxitylocalyx piumicea. 

 Gray, and Iphiteon. p>umicea, Valenciennes, in his division of the Vitreohexactinellida, in 

 the subdivision of " species massive, excavated, shallow," and in a family for which 

 " rosettes or flesh-spicules, many rayed, rays of equal length, straight, capitate, some- 

 times only pointed," were said to be characteristic, while he formed a special family 

 for Dactylocalyx subglohosa, Gray, with the following peculiarities : — " Rosette many 

 rayed, rays of equal length, straight capitate, or with multitudinous rays of unequal 



1 O. Schmidt, Spongienfauua des Atlant. Gebietes, p. 18, 1870. 

 ^ Ann. and Mag, Nat. Hist., ser. 4, vol. ix. pp. 453-457. 



2 Ann. and Mag. Nat. Hist, ser. 4, vol. xii. p. 357. 



