ON FOSSIL SPONGES FEOM METIS. 



51 



10. — Lasiothbix curvicostata, Hinde. 



(Fig. 21.) 



The type form is trausversely oval, 8 mm. iu height by 12 mm. in width, the 

 auchoring spicules cau be traced to a length of 15 mm. from the body. The summit 

 is rounded. There are some nodular elevations of pyrites in the body portion, but it is 



Fig. 21. — Lasiothrix curvicostata. Natural, 

 size and portion enlarged 



doubtful -whether they represent aggregations of spicules or are merely due to the chemi- 

 cal deposition of the mineral, in connection with the presence of organic matter. 



This curious little sponge, of which only one specimen was found, is remarkable for 

 the strong curved spicules which support its sides, giving the appearance of a rounded 

 basket with strong vertical ribs and very slender horizontal bars, within which and at 

 top were quantities of slender straight spicules. 



11. — Lasiothrix flabellata, S.N. 

 (Fig. 22.) 



Fig. 22 — Lasiothrix flahrllata. Restored, 

 and spicules x 5. 



I have some doubt as to the right of this species to be placed in Dr. Hinde's new genus ; 

 but the specimens at first sight resemble the former species, and may accompany it 

 provisionally. The surface appears to be covered with small ovoid bundles of stout 

 biacerate spicules, diverging from the centre and sometimes in fan-shaped tufts- The 

 specimens show indications of an external membrane, and they had somewhat strong 

 root spicules, much larger than those of the body. It seems uncertain whether the fan- 

 shaped bundles are really such or flattened groups of radiating spicules surrounding 

 small oscula. In some specimens the spicules are confusedly scattered in films of pyrit- 



