OF THE SPONGIAD^E. 203 



273, Plate XIV, represents a single hetro-spiculous fibre 

 of the skeleton, X 175 linear. Fig. 377, Plate XXXVI, a 

 portion of the fibrous skeleton with the imi-spiculate 

 secondary skeleton, X 108 linear; and Fig. 234, Plate 

 XXIII, a perfect ovarium of D. vesiculata, Bowerbank, and 

 a portion of a second one showing the interior and the 

 thickness of its walls in its natural state, X 83 linear. 



Suborder VI. Solid siliceo-fibrous skeletons. Skeletons 

 reticulate. Fibres composed of concentric layers of 

 solid silex, without a central canal. Reticulations 

 unsymmetrical. 



Dactyl ocalyx, Stutchbury (Iphiteon, French Museum). 



The structure and mode of growth in this suborder of 

 siliceo-fibrous sponges appears to be precisely the same as 

 that of the kerato-fibrous sponges of the first suborder of 

 the third order Keratosa. 



Dactylocalyae pumicea, Stutchbury, was described in the 

 ' Proceedings of the Zoological Society,' part 9, 1841, p. 86, 

 October 26, 1841. The author describes it thus : " Sponge 

 fixed, siliceous ; incurrent canals uniform in size ; excurrent 

 canals large, forming deep sinuosities on the outer surface, 

 radiating from the root to the outer circumference." 



The sponge was received by the Bristol Museum from 

 Dr. Cutting of Barbadoes. 



The genus Dactylocalyx was established by Mr. Stutch- 

 bury to designate this fine siliceo-fibrons sponge. Half of 

 the type specimen is in the Museum at Bristol, and the 

 remaining portion in the possession of Dr. J. E. Gray of 

 the British Museum. A1 though the sponge was designated 

 Dactylocalyx pumicea, no generic characters were given. I 

 propose therefore to characterise it as follows : 



