der niederen Thiere während des Jahres 1863. 151 



Gen. n. Leuco s olenia. Sponge fistular. formed of a single 

 layer of triradiate and other spicula surrounding a large central 

 cloaca, which extends into all parts of the sponge. Type : Grantia 

 botryoides Flmg. (= Grantia Schm.) 



Gen. Leuconia Gr. Sponge furnished witli cloacae, one or 

 more. Parietes of sponge formed of a mass of irregularly disposed 

 interstitial membranes, and triradiate and other spicula; parmeated 

 by sinuous excurrent canals, the oscula of whicji are irregularly 

 disposed over the surface of the cloaca. Type : Gr. nivea Flg. 



Gen. n. Leti c o qy p sia. Sponge massive, without cloacae; 

 formed of irregularly disposed membranous tissues and spicula. Oscula 

 at the external surface. Hieher L. Gossei n. sp. England und L. 

 algoensis n. sp. 



Ord. IL Silicea. 



Subord. 1. Spiculo-radiate scleletons. Not reticulate. Com- 

 posed of spicula radiating in fasciculi or separately from the base 

 or axis of the sponge. 



Gen. Geodia Lam. Sceleton: spicula fasciculated, radiating 

 from the base or central axis of the sponge to the surface. Der- 

 mis crustular, furnished abundantly with closely packed Ovaria (i. e. 

 global! silicei Schm., die Verf., wie die sog. Gemmulae der Spon- 

 gillen, für Eierstöcke hält). Ovaria siliceous, composed of cuneiform 

 spicula, firmly cemented together by silex, in lines radiating from 

 the centre of the ovary. Pores furnished with oesophageal tubes 

 terminating in the distal extremity of the intermarginal cavities. 

 Intermarginal cavities separate, symmetrical, subcylindrical; each 

 furnished with a membraneous valve at its proximal extremity. (Verf. 

 kennt von diesem Genus 7 verschiedene Arten.) 



Gen. Pachymatisma Bow. Sceleton composed near the exter- 

 nal surface occasionally of short fasciculi of siliceous spicula, dis- 

 posed in lines at obout right angles to the surface of the sponge. 

 Central portion of the sponge unsymmetrical. Alles übrige wie bei 

 Geodia. (Mit drei Arten, unter denen P. Johnstonii n. sp. von 

 England.) 



Gen. n. Ecionemi a. Sponge having a streng axial column 

 or centre of closely packed siliceous spicula disposed in lines pa- 

 rallel to the long axis of the sponge, from which axial column or 

 centre a peripherical System of spicula radiates at about right an- 

 gles. Distal ends of the radii furnished more or less with ternate 

 connecting spicula, the radii of which are disposed immediately be- 

 neath the dermal membrane. Type: E. acervus n. sp. (Mit Anco- 

 rina Schmidt verwandt.) 



Gen. Alcyoncellum Quoy etG. (Euplectella Ow.) Sponge fistu- 



