180 ANATOMY AND PHYSIOLOGY 



which radiate, at about right angles, numerous short 

 simple cylindrical pedicles, or stout fasciculi of closely 

 packed spicula ; the distal ends of each pedestal sepa- 

 rating and radiating in numerous curved lines which 

 spread over the inner surface of the dermal membrane, 

 separating and sustaining it at all parts at a consider- 

 able distance from the central axis of the skeleton. 



Type, Ciocalypia pcnicittus, Bowerbank. 



This genus is allied, by its structural peculiarities, to a 

 certain extent, to Dictyocylindrus, Bowerbank, Hyalonema, 

 Gray, and Alcyoncettum, Quoy et Gaimard. The central 

 axial column of the skeleton is composed of elongated stout 

 reticulations of siliceous spicula, closely resembling the cor- 

 responding tissues of the axial column of a Dictyocylindrus ; 

 but the space between the surface of the column and the 

 inner surface of the dermis is not filled, as in that genus, 

 by the usual interstitial structures of the sponge, it is com- 

 pletely and widely separated from the dermis in a manner 

 very similar to that of the structure of the greatly elongated 

 cloacal appendage of Hyalonema mirabilis, as it appears in 

 its present condition in the most perfect specimens in the 

 British Museum and in the collection of Dr. Gray. There 

 is this difference between the structures of the two genera. 

 The coriaceous dermis surrounding the beautiful spiral 

 axial column of Hyalonema is very thick, and is abundantly 

 furnished with projecting oscula ; and it does not present 

 any indications of lateral pedestals, either on its inner surface 

 or on the surface of the axial column, while these organs 

 are abundant in C. penicillus ; and its dermis also is com- 

 paratively thin and delicately reticulated. 



The dermal portion of the sponge in C. penicillus, and 

 the reticulated tissues on its inner surface, closely resemble 

 the corresponding tissues in Alcyoncellum in their structure. 

 The pores, in number, size, and mode of distribution, are 

 very similar to those of Poh/mastia robusta, Bowerbank ; 

 but the stratum of these reticulated skeleton structures is 

 not so thick in proportion, and in Alcyoncellum and Poly- 



