OJ? THE SPONGIAD^. 357 



COMPOUND STELLATE SPICULA. 

 Fie. 



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 thj^same sponge as Fig. 174. In an 

 early stage of cfevelopment, exhibiting only the 

 primary or axial radii. Page 53. 



(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 ftdly developed, but 

 vdth 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, apicallt 



spiNED. From a specimen of Alcyoncellum, Quoy 

 et Gaimard, in the Museum of the Jardin des 

 Plantes, Paris. X 130 Hnear. Page 54. 



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