258 ANATOMY AND PHYSIOLOGY 



FIG. 



186. One of the radii of the spiculum represented by 



Fig. 185, exhibiting the spination of the apices. 

 X 400 linear. 



187. Part of the axial shaft of a cylindro-rectangulated 



hexradiate spiculum, exhibiting the parts from 

 which the radii would be produced, from the 

 Alcyoncellum in the Museum of the Jardin des 

 Plantes, Paris. X 400 linear. Page 54. 



188. BIFURCATED RECTANGULATED HEXRADIATE STELLATE. 



From the same Alcyoncellum as Fig. 187, in the 

 Museum of the Jardin des Plantes, Paris. X 1060 

 linear. It is minute and slender, and the bifur- 

 cating rays are irregular, often tortuous, and are 

 frequently not produced on one or two of the pri- 

 mary radii. These indecisive characters, common 

 to all the specimens of this form that I have seen, 

 combined with the elongate characters of the radii, 

 seem strongly to mark this spiculum as the con- 

 necting link between the simple hexradiate and 

 the compound stellate forms of spicula. Page 55. 



189. TRIFURCATED ATTENUATO-HEXRADIATE. From 



tetta aspergillum, Owen, having the ray nearest the 

 eye broken off at its base. X 1060 linear. The 

 central radii consist of six rectangulated primary 

 rays of equal length, each of which terminates in 

 three equidistant secondary attenuating rays, which 

 are projected from the apices of the primary ones 

 at an angle of about 45 degrees to the common 

 basal, or primary ray. 

 These spicula occur in abundance in Euplectella 



asperc/ittum, Owen, and in Dactylocalyx pumicea, 



Stutchbury. Page 55. 



190. SPINULO-TRIFURCATED HEXRADIATE STELLATE. From 



Dactylocalyx pumicea, Stutchbury, a perfect spicu- 

 lum. X 1060 linear. Page 55. 



