240 DR. HTNDE AND MR. HOLMES ON SPONGE-llEMATNS 



extending obliquely np-wards. Axial canals very wide in the 

 form figured. Length of distal ray '16 mm., greatest width 

 '042 mm., length of transverse rays '06 mm. In recent sponges 

 the spicule nearest in form to this occurs in Plieroneona Annce, 

 Leidy (see Chall. Eep. vol. xxi. p. 239, pi. xlii. fig. 8). 



PI. XY. fig. 9. Pinule with very short, minutely spined, trans- 

 verse rays, and an elongate tapering distal ray, with some stout 

 conical hooked spines in the lower third of the ray. Length of 

 distal ray '432 mm., width "048 mm., length of transverse rays 

 "032 mm. In the character of the distal ray the pinnies of the 

 recent Hyalonema elegans, Sch. (Chall. Eep. vol. xxi. p. 223, 

 pi. xxxi. fig. 4), approach this form, but the spines are not re- 

 stricted to the lower portion of the raj as in this fossil. 



Pinule spicules are extremely rare as fossils ; hitherto the only 

 forms known are casts in chert from the Jurassic strata of llsede, 

 Hanover, described by Dr. Eiist (' Palaeontographica,' Bd. xxxi. 

 p. 321, pi. XX. fig. 30), and by Wisniowski, from near Cracow 

 (Jahrb. d. k.-k. geolog. Eeichsan. "Wien, Bd. xxxviii. 1888, 4 

 Heft, p. 679, pi. xii. fig. 42). 



Uosette Spicules of Hexactinellid Sponges. 



PI. XV. fig. 10. Eosette in which some o£ the primary rays 

 are furcate whilst others are undivided. The rays are smooth, 

 straight or with a slight curve, and acutely pointed. Diameter 

 of spicule '056 mm., length of secondary rays "021 mm. Spicules 

 of this type are present in Caulophacus latus, Schulze (Chall. 

 Eep. vol. xxi. p. 124, pi. xxiv. fig. 8), already referred to. 



PL XY. fig. 11. Eosette in which each primary ray gives off" 

 four secondary rays. Eays straight, smooth, and acutely pointed. 

 Diameter of spicule "065 mm., length of secondary rays -027 mm. 

 These forms are fairly abundant in the Oamaru material. Eecent 

 spicules of similar character are present in Acanthascus cactus, 

 Sch. (Chall. Eep. vol. xxi. p. 148, pi. 57. fig. 3), from the 

 Japanese Seas. 



GrateromorpJia (a). — PI. XY. fig. 12. Eosette with numerous 

 rays, about 24 can be counted. The rays are stout, cylindrical, 

 straight or slightly curved, extremities capped with convex discs, 

 surrounded by a fringe of about 12 minute teeth. The surface 

 of the rays is minutely tuherculate. The primary rays of the 

 spicule are so short as to be concealed from view, and the secon- 

 dary rays appear to radiate direct from a centre. Diameter 



