Il6 PORIFERA. III. 



(IV, PI. I, figs, i 4) has long, monactinal dermal spicules; it seems to be & Hymedesmia or an Eurypon. 

 Hymedesmia pilata (IV, 59, PI. II, figs. 14), which seems to have no dermal spicules and only sigmata 

 for microsclera, is I think an Eurypon. Finally Hymedesmia pulchella (IV, 61, PI. II, figs. 5 8) seems 

 to be likewise an Eurypon. 



Hymeniacidon paupertas Bow. (Ill, PI. XXXVII, figs. 4 8) I have included in the above table 

 as I take it to be a Hymedesmia, and I think the Myxilla paupertas recorded by Topsent (1904, 

 Fasc. XXV, 168) is another species. The Hymedesmia areolata Thiele mentioned by Kirkpatrick 

 (Nat Antarc. Exp. Nat. Hist IV, PI. 22, figs. 3 3 c) cannot I think be a Hymedesmia and must 

 accordingly be another species. Thiele (Abhandl. Senckenb. nat. Gesell. XXV, 1903, 955) thinks that 

 Myxilla -veneta O. Schmidt is identical with fasciculata Lieberk., and is a Hymedesmia ; I have examined 

 a specimen of Myxilla fasciculata send from Professor von Mare nzeller; it is correct that the species 

 incrusts the chitinuous tubes of Stephanoscyphus, but it has otherwise a reticulate skeleton and is no 

 Hymedesmia; M. veneta I do not know. Hymedesmia norvegica Thiele, which I have included in the 

 above table, is perhaps not a Hymedesmia as it has short skeleton columns; it would thus be a 

 Stylostichon. 



Hymenancora n. g. 



Incrusting, thin forms. The external appearance, the skeleton and the megasclera quite as in 

 Hymedesmia; the microsclera are ancor(B which may be either ancorce spatulifera; or unguiferce ; some- 

 times two forms of ancora occur ; to the ancora sigmata are sometimes added. 



In the introduction to the second part of this work I have, in accordance with the opinions 

 of Levinsen, advanced the view, that species with ancorae and species with chelae should not remain 

 in the same genus, and in accordance herewith I emended the genera Desmacidon and Homoeodictya, 

 Myxilla and Lissodendoryx, and according to the same view I have created the genera Ectyodoryx 

 and Ectyomyxilla (Meddel. om Gronland, XXIX, 1909, 444), the first with chelae, the latter with ancorse. 

 Also the genus Hymedesmia has hitherto included species with chelae and species with ancorae, and it 

 is to comprise these latter species that I create the genus Hymenancora which is in all other respects 

 similar to Hymedesmia. 



So far as I am avare the genus comprises at present the following species: 



1892. H. Pecqueryi Tops. Resultats des camp, scient du Prince de Monaco, Fasc. II, no, PI. XI, fig. 8 



(Myxilla). 



H. minima Tops, ibid., 114, PL XI, fig. 23. (Hymcraphid). 



1904. H. bisctitella Tops, ibid., Fasc. XXV, 191, PI. XV, fig. 3. (Leptosia). 

 H. umbellifera Tops. ibid. 192, PI. XV, fig. 4. (Leptosia). 



1905. H. lae-vis Thiele, Zool. Jahrbiicher, 1905, 453, Taf. 31, Fig. 69 a f. (Hymedesmia). 

 H. tenuissima Thiele, ibid. 454, Taf. 31, Fig. 70 a f. (Hymedesmia). 



1907. H. exigua Kirkpatr. Ann. Mag. Nat. Hist. 7, XX, 273, and 1909, Nat Antarct. Exp. IV, PI. XXII, 

 fig. 4, PI. XXVI, figs. 2 a f. (Hymedesmia). 



