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



Spicules. — (a) Megasclera ; stout, smooth, fusiform oxea (PI. XXIX. fig. 7), bent at 

 more or less of an angle in the middle, sharply and gradually pointed, size about 0*45 

 by 0"04 mm. (a few small, slender styli were also observed, but as these are almost 

 certainly foreign we shall say nothing further about them), (b) Microsclera ; of one 

 kind only ; viz., very abundant isochelse (PI. XXIX. fig. 7a), with well-developed front 

 palms, giving off each a distinct, stout, backward process. The lateral palms are united 

 with the shaft up to their ends (i.e., up to a level with the end of the front j)alm), but 

 the middle portion of the shaft is not fimbriated as in Desmacidon {Homceodictya) 

 herguelenensis ; they are large, handsome spicules about 0"063 mm. long; not infre- 

 quently there is an irregular swelling in the central portion of the shaft. 



This species differs from Desmacidon (Homceodictya) Tcerguelenensis , nobis, in the 

 arrangement of the skeleton, in the larger size of both megasclera (which are here much 

 stouter) and microsclera, in the non-fibriation of the shaft of the latter, and very 

 markedly in external form. In the arrangement of the skeleton it agrees exactly with 

 Desmacidon conidosa, nobis (vide p. 106), and this gives to the two a very similar 

 look ; the two species differ, however, externally, in the arrangement of the oscula 

 and, microscopically, in the form of the isochelate spicules ; yet we think the two come 

 very near together, and in general appearance they are much more like one another 

 than are Desmacidon (Homceodictya) grandis and Desmacidon (Homceodictya) ker- 

 guelenensis (cf. PI. XXII. fig. 1, with PL XXIV. figs. 2 and 3). 



Locality. — Simon's Bay, Cape of Good Hope, November, 1873 ; 10 to 20 fathoms. 

 One specimen. 



Genus Artemisina, Vosmaer. 

 ? 1885. Artemisina, Vosmaer, Sponges of the " Willem Barents" Expedition, 1880 and 1881, p. 25. 



Body compact, texture like that of Suberitidse. Megasclera monactinal ; styli or 

 subtylostyli. Microsclera isochelae and spined toxa, 



Vosmaer's original diagnosis runs as follows : — " Body covered with a thin dermis 

 forming here and there thin oscular tubes. Sponge-mass rather compact, about as 

 Suberites. Generic spicules tr. ac | A sp. | anc^. | 



The only species which we include in the genus is the original type, Artemisina 

 suheritoides. 



Artemisina suheritoides, Vosmaer. 



? 1885. Artemisina suheritoides, Vosmaer, Sponges of the "Willem Barents" Expedition, 1880 



and 1881, p. 25, pi. i. fig. 16; pi. iv. figs. 11-14; 

 pi. V. figs. 51-55. 



As the species has already been fairly fully descril^ed and figured, we can dismiss it 

 very briefly. It is extremely unfortunate that Dr. Vosmaer gives no spicular measure- 



