ON FOSSIL SPONGES FEOM METIS. 



43 



5. — Protospongia ctathiformis, S.N. 

 (Figs. 13 aud 14. PI. Ill, fig. 5.) 



Fin. 13.- — Protoaporigia cyathi- 

 formis. Restored . 



Fig. 14. — ProlosffMnyia cyathiformin. Primary, secondary 

 and tertiary cruciform .spicules, x 5. 



General form inverted couical. Wlieu mature about 3 cm. wide at top and 5 cm. 

 long without the anchoring spicules which are at least an inch long. Top truncate as 

 if with a wide osculum, with a few short defensive spicules on its margin. Primary 

 body spicules cruciform with long rays, in some 2 to 3 mm. in length, loosely attached 

 or free, but forming large rhombic meshes, secondary aud tertiary spicules numerous and 

 delicate with slender arms. Root spicules short, simple, about fiA^e visible in the most 

 perfect specimens and passing np to the middle of the body. Indications of many 

 interior minute flesh spicules often constituting a pyritised mass, obscuring the meshes. 



The oblique character of the transverse spicules deserves notice, but this may be 

 the result of compression, though I think it more likely that it is an original feature. 



This species is well characterised by its form, and by its multitudes of very minute 

 cruciform spicules. These and the fact of the sponge being often represented by a dense 

 pyritous mass indicate a thick and fleshy body-wall. 



G. — Protospongia delicatula, S.N. 

 (Fig 15.) 



Fig. 15. — Prolosfpomgia delicalula- {a) Restored. 

 ih) Portion of base enlarged. 



Grlobular or oblong in form, from 1 to 4 cm. in greatest diameter. Body spicules 

 cruciform, very numerous, and extremely small. Some specimens show what seems to 



