OJt 1 THE SPONGIAD^E. 257 



COMPOUND STELLATE SPICULA. 

 FIG. 



174. ATTENUATED RECTANGULATED HEXRADIATE. X 90 



linear. From Euplectella aspergillum, Owen. A 

 fully developed spiculum. Page 52. 



175. ATTENUATED RECTANGULATED HEXRADIATE. X 90 



linear. From the same sponge as Fig. 174. In an 

 early stage of development, exhibiting only the 

 primary or axial radii. Page 52. 



[176. Progressive degrees of development of the secondary 

 | 177. radii of the same form of spiculum represented by 

 [178. Fig. 174. X 90 linear. Page 52. 



179. The same spiculum as Fig. 175, with one secondary 



ray fully developed. X 90 linear. Page 52. 



180. The same spiculum as Fig. 175, having two secondary 



rays forming a right angle with each other, fully 

 developed. X 90 linear. Page 53. 



181. The same spiculum as Fig. 175, with two secondary 



rays developed in opposite directions. X 90 

 linear. Page 53. 



182. The same spiculum as Fig. 175, with three secondary 



rays forming two right angles with each other. 

 X 90 linear. Page 53. 



183. The same form of spiculum as Fig. 174, with the 



whole of the secondary radii fully developed, bat 

 with one only of the axial radii produced. X 90 

 linear. Page 53. 



184. SLENDER ATTENUATED RECTANGULATED HEXRADIATE. 



From Euplectella aspergillum, Owen. X 90 linear. 

 Page 54. 



185. CYLINDRO-RECTANGULATED HEXRADIATE, APICALLY 



SPIN ED. From a specimen of Alcyoncellum, Quoy 

 et Gaimard, in the Museum of the Jardin des 

 Plantes, Paris. X 130 linear. Page 54. 



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