IN THE LOWER TERTIARY STRATA OF NEW ZEALAND. 243 



head-rays these spicules singularly resemble the head-rays of 

 Samus anonyma, Grray, as figured by Mr. Carter (Ann. & Mag. 

 Nat. Hist. s. 5, vol. iii. 1879, pi. zxix. fig. 3), but the spicules of 

 this sponge have similar trif urcate rays at both ends of the shaft. 

 A detached spicule resembling fig. 14, but having three noimal 

 rays, is figured by Bovverbank as probably belonging to a species 

 of Dactylocalyx (Proc. Zool. See. 1869, pi. iii. fig. 16), but this 

 is an error, since this genus is bexactiuellid. 



Summary of Genera and Species of TetractineJIid and LWiistid 

 Sponges represented in the Oamaru Deposit. 



TETRACTINELLIDiE. 

 No. of Species. 



4 sp. Corticium, Osc. Schmidt. 



1 sp. Flakina, F. E. Schulze. 



2 sp. Fachastrella, Osc. Schmidt. 



1 sp. Triptolemus, Sollas. 



2 sp. DitricBnella, g. n. 



6 sp. Geodites, Carter, Stelletta, Osc. Schmidt, 



and allied genera. 

 2 sp. Erylus, Grray. 

 2 sp. TetJiya, Lamarck. 

 2 sp. Grenus undetermined. 



22 



sp. 



LiTUISTIDiE. 



1 sp. Lyidium, Osc. Schmidt. 



1 sp. Vetulina, Osc. Sclimidt. 



2 sp. Corallistes, Osc. Schmidt. 

 2 sp. Discodermia^ Bocage. 



1 sp. Grenus undetermined. 



7 sp. 



From these lists it appears that there are 22 species and 9 

 genera of Tetractinellid sponges, and only 7 spetties and 5 genera 

 ot'Lithistid sponges in the Oamaru deposit. These numbers can 

 only be considered as approximate, but it is probable that they 

 are under rather than overestimated. Though iu the number 

 of species the Tetractinellid sponges fall far short of the Monac- 

 tiuellids, yet in certain portions of the rock their remains far 



17* 



