PORIFERA. I. 99 



On account of the rather considerable differences with regard to the spicnlation, I take the two 

 varieties trirliapliis 3.\\(S. fistulosa estabHshed by Top sent i Rev. Suisse de Zool. IV, 1897, 461, PI. XVIII, 

 Fig. 9, PI. XXI, Fig. 35; 462, PL XVIII, Fig. 11), to be independent species, and this opinion may, I 

 suppose, also hold good with regard to Fristedt's variety stcllifera, the spiculation of which is quite 

 peculiar. 



Kieschnick (Semon: Zool. Forschungsreisen in Austr. Band V. Denkschrift. Med. Nat. Gesellsch. 

 Jena, Band 8, 1900, 568, Tab. XLV, Fig. 53—56) establishes a Dcsinacclla fragilis from Amboyua, whose 

 spiculation of microsclera is given thus: grosse Doppelhaken, Sigma, zarten Bogen, Trichodragmen , 

 but neither from the ver}- incomplete description nor from the figures (the zarten Bogen are not 

 figured) can anything be seen but the fact that the species belongs to the present group. 



I shall further call attention to the fact that the genus Sigiiiaxinclla with the species mistra- 

 liaiia Dend., flabcllata Cart, and ciocalyptoidcs Dend., established by Dendy (Proceed, of the Roy. Soc. of 

 Vict. IX, 1897, 240) and referred to Axinellidcr, would, according to the descriptions in hand, scarcely 

 seem to be different from Dcsmacclla. 



Tops en t, in 1892, enumerates the Dcsviacella-s^&ci^s then known to him, and mentions six; 



of these Pcachii and aberrans are mentioned above; of the other four annexa has here been referred 



to the genus Bicvima. The other species are: pumilio Schm., vagabimda Schm., and caver mda Bow. 



With regard to pumilio and vagabunda it is, on account of the shortness of the description, impossible 



to form any nearer opinion; with regard to vagabunda there ma)-, perhaps, be some probability that 



it ma>- be a Desmacella. Later has, besides the species mentioned above, one more species supervened, 



viz. the D. vulgaris, established by Topsent 1892 (Arch, de zool. exp. et gen. X, 1892, XXI). Besides the 



ten Dfsiiiacclla-s.]i&c\<is belonging to one group, which are enumerated abo\-e, the genus consequently 



still comprises the following: 



Dcsmacclla pumilio Schm.? 



» vagabunda Schm. ? 



» cavermda Bow. 



» vulgaris Tops. 



Hamacantha Gray. 



The form varying, massive, roundish or quite irregular, sometimes more or less erect, or finally 

 crust-shaped; sometimes provided with papilla:. The skeleton is an irregular nctivork of mostly poly- 

 spicular fibres and irregularly scattered spicules and bundles of spicules. Spongin is present to a small 

 degree, or wanting. Spicula: Megasclera styli, sometimes oxea interspersed betz^'cen the styli. or exclu- 

 sively oxea. Microsclera ; the microsclera characteristic of the genus, are diancistra of one to three 

 different forms, together with which may be found toxa, trichodragmata. or sigmata. 



I. H. Bowerbanki n. sp. 

 PI. VII, Figs. 2— 3, PI. XVIII, Fig. I a— k, Figs. 2— 3. 

 1874. IHaUchondria falcula Bowerbank, Mon. Brit. Spong. Ill, 208, PI. LXXIV, figs. 1—3. 

 1882. Hymedesmia fohnsoni Carter, Ann. Mag. Nat. Hist. Ser. 5, IX, 297, PL XI, fig. 20 a— e. 



13* 



