40 C. F. JEN KIN. 



(/■) Small alatc liUiuliiradiatcs forming the I'dge. Basal ray 14()/j. X >s /x, 

 straio-ht, tapering uniformly to a .sharp point. Paired rays bent slightly 

 downwards, about 70 ^ X 10 ju. Apieal ray short and eonical, -JO /a long x 

 8 fi thick at base, perpendicular to facial plane. Oral angle nearly 180°. 



M EOAPOnON POLLKJARLS.* 



(Plates XXXVil. and XXXVTll.. Figs. 125-1:?0.) 



There are two .specimens of this new .s2)ecies in the collcrtion : the larger one is fi.xed 

 in osmic acid and is cou.sequently brown ; the smaller one, which is fixed in alcohol, is 

 white ; both are hispid. The larger specimen is in the form of a flattened tube 15 mm. 

 long. The diameter at the widest part near the middle is 3 mm. The smaller 

 specimen is ovoid, 2l mm. x U mm. Thei'e is a large gastral cavity which terminates 

 in the oscule, which in both specimens is bent to one side. The larger specimen has an 

 oscular collar about I nun. long. 



The structure of the body-wall is shown in Fig. 120. The space between 

 gastral and dermal layers is tilled up with three or four layers of flagellated chambers. 

 Each flagellated chamber is surrounded by a slender skeleton of minute prickly hastate 

 o.xea (.see Fig.s. 129 and 127) ; these oxea often lie together in small bunches of 

 three or four, and as they may lie parti}' on one and partly on another chamber, they 

 build up serpentine lines of minute spicules Ihreading about between the chand>ers. 

 Some of the.se minute oxea also lie in the gastral and dermal hiyei's, and .ilso in the 

 columns supporting the dermis. 



Canal System. — There is an incurrcnt chamber under the dermal layer which is 

 prt)babl\- continuous round the whole body of the sponge. The dermal layer is 

 supported over this chandicr by columns of spicules consisting partly of the basal rays 

 of the chiactines and [)artly of oxe.-i which project outside the dermis. The incuirent 

 canals lead inwards from the incuiicnt chambers. The excurrent canals are connected 

 in groups to excurrent chambers which open into the gastral cavity through large 

 ports ; these are more or less surrounded by the apical rays of the chiactines (sec 

 Fig. 12.-)). 



The Skeleton. — The dermal skeleton is formed by a dense layer, Ave or .six 

 spicules thick, of triradiates, pierced at intervals by the projecting bunches of oxea. 

 The l)ody skeleton cou.sists of chiactines and a very few scattered triradiates. The 

 basal ravs of the chiactines are bunched more or less together at their distal ends and 

 occasionally project through the dermal la>'cr ; with each bunch are grouj^ed a number 

 of the oxea, which project with their thicker bent ends about ouc-third of their length 

 beyond the dermis. There is no special gastral skeleton ; the gastral cortex (see Fig. 

 loO) is supported by the paired rays of the chiactines, and a few minute oxea 

 irregularly scattered. 



* Pollicaris = '• lilio ;i tluuub," iianiocl from the sluipc of the oxea. 



