186 M. E. Hackel's Prodromus of 



Family X. Ccenostomida, H. 



Character. The mature calcareous sponge forms a stock 

 with a single mouth-opening, the stomachal walls of which 

 are traversed by irregularly branched canals. 



Genus 29. *Ccenostomella, nov. gen. 



Gen. char. The persons of the stock are united into a single 

 mass, the common mouth-opening of wliich is produced into a 

 thinly membranous proboscis, whilst the stomachal cavities of 

 the persons remain separated. One species. 



111. *(7. caminus, H. Antilles. 



Order IV. CLISTOSYCA, H. 



Character. The mature calcareous sponge forms ojie per.5(??i 

 without a mouth-opening. (The body usually appears under 

 the form of an ovate, spheroidal, or compressed bladder, the 

 internal cavity of which communicates with the surrounding- 

 water only by cutaneous pores or parietal canals, but by no 

 large orifice (mouth) ; the mouth is closed up.) 



Family XI. Clistolynthida, H. 



Character. The mature calcareous sponge forms a person 

 without a mouth-opening, the wall of which is traversed by 

 simple cutaneous pores (as in the Olynthida). 



Genus 30. *Clistolynthus, nov. gen. 



Gen. char. Stomachal cavity simple, without partitions. 

 One species. 



112. * (7. vesicula,ll. Honolulu (Haltermann). 



Family XII. Sycocystida. 



Character. The mature calcareous sponge forms one person 

 without a mouth-opening, the body- wall of which is traversed 

 by regular radial canals (radial tubes) as in the Sycarida. 



Genus 31. *Sycocystis, nov. gen. 



Gen. char. Stomachal cavity quite simple, without com- 

 partments. Three species. 



113. *>5. oviformis, H. Heligoland (H.). 



114. *S. compressa, H. Norway. 



115. S. utricuhis, a. {Ufe utriculus^O.S.). Greenland. 



