HOLASCELLA TARAXACITM. 29 



is distinguished from it by the possession of discohexasters ; another, H. stellatus, 

 by the possession of oxyhexasters (heinioxyhexasters) with strongly curved rays; 

 and a third, H. fibulatus, which also has sigm microscleres, by the absence of oxy- 

 hexasters. The fourth, H. obesus, which appears to differ from H. edwardsii 

 only by its thicker body-wall and by having hypodermal hexactines with some- 

 what longer distal ray, seems to be more closely aUied to it. But the material 

 on which F. E. Schulze bases this species was very fragmentary and his descrip- 

 tion of it is somewhat incomplete. Therefore quite apart from the absence of 

 ring-sigms in H. obesus and their presence in H. edwardsii, I should hesitate 

 pronouncing these sponges, found respectively off Enderbyland in the Antarctic 

 and off Peru in the Pacific, as specifically identical. 



Tubular EuplecteUidae (Euplectellinae) with root-spicule bundles and 

 (probably) without parietal apertures. The body-wall is supported by a net- 

 work of stout hexactines, pentactines, or tetractines held together by slender 

 comitals. To discohexasters or microdiscohexactines, other hexasters, micro- 

 hexactine forms, and pentactine and tetractine derivates of these may be added. 

 The hypodermals are hexactines with spiny distal ray. The root-spicules are 

 long, smooth shafts (rhabds or the long radial rays of pentactine anchors, the 

 distal ends of which have been lost) and monactines with oblique, backwardly 

 directed spines and a distal tyle, from which arise similar spines, representing 

 anchor- teeth. The morphological centre (axial cross) of these spicules is situ- 

 ated in the terminal anchor- tyle. 



The collection contains two more or less complete specimens and four frag- 

 ments, which belong to three species, all of which are new. 



Holascella taraxacum, sp. nov. 

 Plate 21, figs. 1-13; Plate 22, figs. 1-41; Plate 23, figs. 1-3. 



One specimen, the upper end of which is missing, but which is otherwise 

 fairly complete, and three fragments of this species were trawled in the Eastern 

 Tropical Pacific at Station 4649, on 10 November, 1904; 5° 17' S., 85° 19.5' W.; 

 depth 4086 m. (2235 f.); they grew on a bottom of fine, sticky, gray mud; the 

 bottom-temperature was 35.4°. 



The specific name refers to the sinularity of the abundant discohexasters 

 to the seed-balls of Taraxacum. 



