m THE LOWER TEKTIART STRATA OF NEW ZEALAND. 261 



Figs. 28, 29, 30. Different forms of skeletal spicules of Tetracladine lithistids, 

 X50. 



31, 32, 33. Different forms of skeletal spicules of Anomacladine lithistid, 



Vetulioia Oamaruensis. X 200. 

 Fig. 34. Modified trifid spicule of Triptolemus australis. X 40. 

 Figs. 35-40. Different forms of calthrops s^icMlesoiPachastrella. Figs. 36, 3S, 



40 X 40 ; fig. 3.5 X 100 ; figs. 37, 39 X 200. 



Plate XIV. 



Figs. 1, 7. Trifid spicules of the dermal layer of lithistid sponges. Corallistes 

 (a). Fig. 1 X 200 ; fig. 7 X 50. 

 2, 3, 5. Modified trifid spicules of the dermal layer of Discodermia (a). 

 X 40. 

 Fig. 4. Modified trifid spicule of the dermal layer of Thconella (a). X 40. 



6. Dermal spicule of Corallistes (?). x 40. 

 Figs. 8-11. Different forms of lithistid dermal spicules of i>Jsco(^er?Kia. X 100. 

 Fig. 12. Dermal spicule of Discodermia sinuosa. X 100. 



Figs. 13, 14. Modified dermal spicules in which each of the head-rays is tri- 

 furcate, genus undetermined. X 200. 

 15, 16. Stellate spicules of SteUetta (d). X 300. 



17, 20, 22, 24. Globostellate spicules of Tethya (a). Figs. 17, 20 X 100 ; 



figs. 22, 24 X 300. 



18, 18 a, 21. Small globosteilate spicules of Geudites (?). X 600. 

 Fig. 19. Globosteilate spicule. X 200. 



Figs. 23, 31. Small globostellates of Pac'hastrella (a). X 600. 



25, 20, 27. Stellate spicules with spined rays. Figs. 25, 26 X 200 ; fig. 27 



X 600. 

 28, 29, 30. Globosteilate spicules with truncate and spined rays of Stel- 



letta (b). X 200. 



32, 32 a. Globate spicule of Geodites. X 200.— Fig. 32 a. A portion of 



the surface of fig. 32, still more enlarged, showing the spined heads 

 of its minute component spicules. X 600. 



33, 34. Two forms of discoidal spicules of Erylus (a), (b). x 200. 



35, 36, 37. Dermal spicules of unknown sponge, Bactylocalycites, Carter. 

 X 200. 

 Fig. 38. Dermal (?) spicule of unknown sponge. X 200. 



Plate XV. 



Fig. 1. Spined acerate spicule of Hexactinellid. X 200. 



Figs. 2, 3, 4. Different forms of six-rayed pinule spicules of Caulophacus and 



allied genera. X 200. 

 Fig. 5. Short truncate pinule with five rays. X 600. 



Figs. 6, 7, 8, 9. Different forms of five-rayed pinule spicules of Hyalonema and 

 allied genera. Figs. 6, 7, 8 X 200 ; fig. 9 X 100. 

 10, 11. Two forms of i-osette spicules of Hexactinellid. X 300. 

 LINN. JOURN. ZOOLOGY, VOL. XXIV. 19 



