278 ANATOMY AND PHYSIOLOGY 



FIG. 



302. Two groups of inhalent pores in the dermal mem- 



brane, situated immediately above the distal ends 

 of the intermarginal cavities of Geodia Barretti. 

 X83 linear. Page 171. 



303. A portion of the dermal surface of If afic/tondria pani- 



cea, Johnston, showing the multispicular network 

 for the support of the dermal membrane and the 

 open pores in the areas. X 108 linear. Pages 

 108 and 195. 



304. A small portion of the dermal membrane of Ti'thea 



muricata, Bowerbank, MS., exhibiting the pores in 

 an open condition. X 108 linear. Pages 25 and 

 108. 



305. A small portion of the same piece of membrane, 



highly magnified, to show the positions of the 

 elongo-stellate defensive spicula on the external 

 surface of the dermal membrane. X 183 linear. 

 Pages 25 and 108. 



306. Represents the inner surface of the clermis of Dactylo- 



calyx Prattii, Bowerbank, MS., showing the manner 

 in which the apices of the radii of the ternate spicula 

 forming the inhalent porous areas, are spliced on 

 each other to allow of the expansion and contrac- 

 tion of the dermal surface. X 108 linear. Pages 

 18, 19 and 101. 



307. Represents a portion of the dermal surface of an un- 



described sponge from the East Indies, having 

 numerous depressed porous areas furnished with 

 stqmata-like protective organs, a, the protective 

 organ in a perfect condition ; 6, having the pro- 

 tective organ removed to exhibit the deeply 

 depressed porous area. X 50 linear. 



308. A portion of the sponge represented of its natural 



size, with two large oscula and numerous inhalent 

 areas. 



309. A small portion of the single-scried dermal spicula r 



network of Isodictya variant, Bowerbank. X 

 linear. Page 10 s *. 



