[DAWSON] FOSSIL SPONdES AND OTHER ORGANIC REMAINS 



US 



tlie 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. 



12. — Lasiothrix flabellata, s. n. 

 (Fig. 25.) 



Fig. 2b.— Lasiothrix flabellata. Re.stored, 

 and spicules x 5. 



I have some doubt as to the right of this species to be placed in Dr. 

 Hinde's new genus; biit the specimens mucli resemble the former species, 

 and may accompan}^ 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 w^hether 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 tilms of pyritous matter with little indication of radiating 

 arrangement. Dr. Hinde remai"ks as to this form that " the spicules do 

 not stand out detinitely, as in the case of the hexactinellid sponge spicules, 

 but appear to be imbedded in some membrane. In two instances, anchor- 

 ing-spicules, like those of Protospongia, project from the base of the 

 mass. I do not know of any monactinellid sponge furnished, as these 

 appear to have been, with long anchoring-spicules." 



The .sponges of this genus are very rare in the Metis collections, and 

 are obscure and ditlicult to make out as to their details. 



