CALCAREA. 19 



Spicules (Figs. 55 and 56). 

 The Oxea an off on* sort : 



(</) Very large bent projecting oxea, of all size* from 400 M to 1,830/t long, x 

 20 M to 33 M thick, pointed at both ends, usually straight for alwut two- 

 thirds of their length, then l>cnt at two or three points angularly, the end 

 being often bent through a total angle of 125 from the axis of the 

 straightcr portion of the spicnle. The [joints where the angular In-nds 

 occur are often marked on the convex Hide by flattened areas, a* if the 

 spicule had Iwen deflected by contact with a plane surface. 



The Tri radiates are of one sort : 



(li) Alate tri radiates of very variable Kha{x>. There is no distinction lictwecu 

 the gastral, Ixxly wall and dermal triradiatea. Basal ray straight, tapering, 

 sharply pointed, 190^ to 360 M long x 10 M to 14 M thick. Paired rays 

 straight or bent slightly up or down, 160^ to 220 M long x 10 M to 14 M 

 thick. Tapering slightly and rather bluntly pointed. Oral angle 110 to 

 145. 



"idriradiate*. There is one sort of quudri radiate : 



(?) Alatc quadriradiates from the gastral cortex, Iwsal ray straight, tajtoring to 

 a sharp point, 280 M long x 12 M thick. Paired rays equal, slightly bont 

 upwards, 140 to 220^ long x 10 to 12 M thick. Oral angle alnmt 130 

 folded backwards, i.e. away from the face taaring the apical ray. Angle of 

 fold about 170. Apical ray 40 M long x 8 to 10 M thick, sharply pointed, 

 l>ent orally. 



Oscular spicules. 



(/) The oscular fringe consists of short club-shaped oxea tapering to a point at 

 the inner end and bent near the outer end, which is rounded, I .'><>/ to 

 230 M long x 12 M to 45 M thick. The thicker spicules are the commonest. 

 The tri radiates at the edge have an oral angle of nearly 180. 



LKITANDRA HIBKRNA.* 

 (Plate XXXI., Figs. 57-58.) 



There are two specimens of this new species in the collection, one straight, vase- 

 sliajied. 7 mm. x l mm., the other bent through at right angle, 6 mm. x 1 mm. In 

 colour they are dull yellow as preserved in spirits, and appear" minutely hispid to the 

 naked eye. 



Tin- structure of the l>ody wall, which surrounds a large gastral cavity, is shown in 



Most of the specimens were OflBtlrtH at the ' Diacovcrj ' ' Winter Quarter*. 



