48 



COELEN TEE ATA SPONGI AE 



CLASS I 



phery, and with, finer radial canals leading from exterior to cloaca. Skeleton 

 composed of irregular smooth -rayed tetraclons with root-like branching 





FIG. 54. 



Callopegma acaiile, Zitt. Senonian ; Ahlten, Hanover ; a, Individual in 2/4 natural size ; fe, Skeleton mag- 

 nified 40/i 5 c > Portion of periphery, 2 /i ; d, Same magnified 40/j, and showing anchors with furcate head-rays. 



extremities, disposed in rows parallel to the radial canals. Occurs (usually 

 replaced by calcite) in the Ordovician of the Eussian Baltic Sea Provinces, 



FIG. 55. 



Phymatella tulerosa, Quenst. sp. Quadratenkreide 

 (Upper Senonian) ; Linden, near Hanover, a, Sponge, 

 1/2 natural size; 6, Outer surface, 1/1 5 c, Skeletal 

 element, so/j ; d, Spicules from stalk portion, 50/j. 



Siphonia tulipa, Zitt. Greensand ; Blackdown." 

 A, Longitudinal section, natural size. B, Sponge with 

 peduncle and root, 1/2 natural size (after Sowerby). 



Ordovician of Illinois, and Silurian of Gottland. Also in erratic blocks on the 

 plains of Northern Germany, usually chalcedonised. 



Archaeoscyphia, Hinde. Cambrian. 



Callopegma, Zittel (Fig. 54). Bowl- or funnel-shaped, short-stemmed, thick- 

 walled. External surface perforated by smaller, internal by larger canal-openings 

 (ostia and postica). Skeleton composed of smooth-rayed tetraclons, the digitate 

 extremities of Avhich are inflated into balls. Dermal spicules in the form of 

 anchors and rods. Upper Cretaceous. 



Phymatella, Zittel (Fig. 55). Upper Cretaceous. 



