Preliminary Account of Synute Fulchella. 5 



spicules having the apical ray projecting outwards and 

 slightly upwards into the gastral caWty. The oral angle is 

 a good deal wider than the lateral, and the oral rays often 

 markedly longer than the basal, measuring, for example, 0-15 

 by ()0]4 mm., as against 08-t by 001 -t mm. The dispro- 

 portion, however, is not always so great as this, nor are the 

 spicules always so large. The rays are stout, conical and 

 gradually sharp-pointed, and the oral rays curve slightly 

 away from one another. The apical ra}- is usually short and 

 stout, conical, gradually sharp-i)ointed and nearly straight, 

 although inclined upwards ; usually only about OOoG mm. 

 long, rarely a good deal longer. Amongst these quadri- 

 radiates are found a number of sagittal triradiates, while at 

 a sliort di-tance below the osculum the quadrirailiates 

 gradually disappear, leaving triradiates only. We ma}^ call 

 these latter the sub-osculai- gastral triradiates. The sub- 

 oscular gastral triradiates are arranged ver\' regularly, like an 

 articulate tubar skeleton, with the basal raya all pointing 

 away from the osculum. They are all sagittal ; at lirst {i.e., 

 away from the osculum) the basal ray is the longest and the 

 oral rays are nearly straight, diverging at a very wide angle. 

 All the rays are conical and gradually sharp-pointed. The 

 oral rays measure about O'l by OOl mm. and the basal about 

 014 by 001)8 mm. On approaching the osculum t\\e>e 

 .sagittal triradiates gi-adually become smaller and their shape 

 gradually changes, the basal ray becoming very short (much 

 shorter than tlie oral rays) and the oral rays spread out 

 almost in a line with one another. The rays are still 

 conical and gradually sluirp-pointed. In the extreme form, 

 found just within the osculum, the oral rays may still 

 measure about 1 mm. in length while the basal is reduced 

 sometimes to 002 mm. and is also much slenderer than the 

 orals. 



The Oscuhi.r Skeleton. — This consists oi a clo.seh- packed 

 layer of long, slender oxea arranged vertically side Viy side 

 around the o.sculum, but the greater part of the spicule is 

 imbedded in the wall of the gastral cavity, so that there is 

 no conspicuous oscular fringe. These oxea, except for their 

 much greater size, resemble the small surface oxea of the 

 cortical skeleton. They are long and slender, usually 

 gradually sharj)-pointed at their inner ends and irregularly 

 hastate at theiv outer ends. They measure about OS by 



