176 ^I. E. Hiickcrs Prudrounis of 



XVIII. — Prodroinus of a St/stem of f lie Calcareous Sjwnges. 

 By Ernst IlACKKLf. 



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

 M.-M. = Milducho-Maclny. 11. = Iliickel. An * before the name of a 

 genus or species indicates that it is new. 



Legion CALCISPONGIyE, Blainville. 



(Svnonvms: Grantftc, Fleming; >S)jon^<Vc m/careo?, Bower- 

 bank.) 



Sponger witli a skeleton composed of carbonate of lime. 



Order 1. MONOSYCA, 11. 



Character. The mature calcareotis sponge forms a single 

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

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

 cavity of tlie body] simple or chamberetl, always with a sim- 

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



Family 1. Prosy cida, II. 



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. *Prosycum, nov. gen. 



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

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



l.*P. simplicissimum, IT. Naples (H.). 



2. *P. prtmorJiale, H, Naples (II. \ 



Family II. Ol3rnthida, H. 



Character. The mature calcareous sponge forms a simple 

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

 borly-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, withoitt 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. 23&-264, by 

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



