176 M, E. Hiickel's Prodromus of 



XVIII. — Prodromus of a System of the Calcareous Sponges. 

 By Ernst Hackel t- 



Note. — J. = Johnston. Bb. = Bowerbank. 0. S. = Oscar Schmidt. 

 M.-M. = Miklucho-Maclav. H. = Hackel. An * before the name of a 

 genus or species indicates that it is new. 



Legion CALCISPONGI^, Blainville. 



(Synonjms : Grantioiy Flenling ; SjJongke caJcarece^ Bower- 

 bank.) 



Sponges with a skeleton composed of carbonate of lime. 



Order I. MONOSYCA, H. 



Character. Hie mature calcareous sponge forms a single 

 person with a single mouth-opening. (Body usually cylindrical, 

 fusiform, or ovate, not branched. Stomachal cavity [inner 

 cavity of the body] simple or chambered, always with a sim- 

 ple mouth-opening placed opposite to the point of adhesion.) 



Family I. Prosy cida, H. 



Character. The mature calcareous sponge forms a simple 

 sac-like person, furnished with a single mouth-opening, the 

 body-wall (stomachal wall) of which is quite solid, and not 

 perforated. 



Genus 1. *Peosycum, nov. gen. 



Gen. char. Mouth-opening simple, without any peristomial 

 crown (without a circlet of projecting spicules). Two species. 



l.*P. simplicissimmn ^ H. Naples (H.). 



2. *P. primordiale^ H. Naples (H.). 



Family II. OlyntMda, H. 



Character, The mature calcareous sponge forms a simple 

 sac-like person furnished with a single mouth-opening, and the 

 body-wall (stomachal wall) of which is perforated only by 

 simple cutaneous pores. (The cutaneous pores are simple in- 

 terstices in the parenchyma, without any special lining.) 



Genus 2. *Olynthus, nov. gen. 



Gen. char. Mouth-opening simple, without any peristomial 

 crown (circlet of freely projecting spicules). Five species. 



3. * 0. simplex, H. Naples (H.). 



t Translated from the * Jenaische Zeitschrift,' Band v. pp. 236-254, by 

 W. S.Dallas, F.L.S. 



