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



As appendix to the Euretidse I must here mention two small sponges, which in form 

 and structure undoubtedly belong to this family, though they neither agree with any of the 

 species described above, nor yet were sufficiently differentiated to admit of adequate and 

 distinct specific diagnosis. 



They form two small thin-walled funnels, 1 and l^ cm. in height, fixed on a small 

 basal plate, Avith a terminal aperture above, 5 to 7 mm. in width, and with several short, 

 tubular, stump-like lateral openings. They thus appear to be young individuals from 

 which a Eurete or Periphragella or even Lefroyella might quite well develop. They 

 agree with one another so thoroughly, both in macroscopic and microscopic characters, 

 that they unquestionably belong to the same species. They were both trawled off Little 

 Ki Island, at Station 192, from a depth of 140 fathoms and a blue mvid ground. 

 The dictyonal framework generally resembles that of species Ezirete. The beams are 

 thickly beset with coarse and fine tubercles in irregular disposition, and exhibiting a 

 distinct thickening of the nodes of intersection, and also short freely projecting conuh 

 (PI. LXXII. fig 4). The parenchymalia are of variable size, and lie at right angles to 

 the two bounding surfaces. They are represented by rmcinates, and by oxyhexasters 

 with short principal rays, and rarely with two longer slightly curved terminals on 

 each principal (PL LXXII. fig. 7), and also by discohexasters in which the short 

 principals bear a number of long slightly curved terminals with marginally toothed 

 terminal discs (PL LXXII. fig. 8). 



The dermal skeleton consists of hypodermal pentacts, in which the four tangentials 

 and also the radial proximal ray are at their ends somewhat roughened and slightly 

 pointed or rounded at the tips. Beside the radial ray of these hyjoodermalia there lie 

 radially directed scopulse, in which the shaft is pointed at the inner end, while the outer 

 exhibits a thickening with four or five slightly curved or even geniculate, thin, smooth, 

 terminal rays, in which the club-shaped terminal knobs are equipped with barbs 

 (PL LXXII. figs. 5, 6). 



On the gastral surface I could only recognise pentact hypogastralia, which resemble 

 the hypodermalia (PL LXXII. fig. 4). 



Family II. M e l i t t i o n i d ^, Zittel (Pis. LXXXIII.-LXXXVL). 



Scopularia which have the form of a ramified tube or of a cup mth lateral blind 

 diverticula. The dictyonal framework forms somewhat regularly hexagonal open radial 

 spaces. In each of these a funnel-shaped, outstretched continuation of the reticular 

 membrane of the ciliated chambers extends across the lumen. This is covered 

 further along the external surface by the dermal membrane and on the internal surface by 

 the gastral, stretching flatly over the various apertures. The gastral skeleton includes 

 no scopulse. 



