OF THE SPONGIAD^E. 237 



FIG. 



58. SPICULATED PORRECTO-TERNATE. Having three equi- 

 distant porrect terminal rays, and a fourth or 

 central one in a line with the axis of the shaft. 

 From Geodia Barretti, Bowerbank, MS. X 90 

 linear. 



PREHENSILE SPICULA. 



59. APICALLY SPINED RECURVO -QUATERNATE. From 

 Euplectella cucumer, Owen. X 90 linear. Pro- 

 jected from the basal portion of the sponge as a 

 means of attachment to other bodies. The recurvo- 

 quaternate end (a) being the apex of the spiculum. 

 Page 20. 



DEFENSIVE SPICULA. 



60. MULTIDENTATE BiROTULATE. Hyalonema mirabilis, 



Gray. X 83 linear. This form is more especially 

 a retentive spiculum ; an auxiliary to the offensive 

 and defensive spiculated cruciform spicula with 

 which it is associated in the interstitial cavities of 

 the sponge. Fig. 294. 



From the basal portion of a specimen in the British 

 Museum. Pages 37 and 127. 



61. ELONGO-RECURVATE DENTATO-BIROTULATE. From the 



same sponge as Fig. 60. X 308 linear. 



62. RECURVO - ACUTELY DENTATE - BIROTULATE. From 



soundings in the Indian Ocean, 2200 fathoms ; 

 probably from an unknown species of Hyalonema. 

 X 308 linear. 



63. ELONGO-RECURVATE DENTATO-BIROTULATE. From 



soundings in the Indian Ocean, 2200 fathoms; from 

 most probably an unknown species of Hyalonema. 

 X 308 linear. 



