Porifera. 



found 22 species of Tetractinellidae belonging to the genera Corticium, Pla- 

 kina, Pachastrella, Triptolemus, Ditriaenclla n. g., Geodites, Stelletta, Erylus, 

 Tethya. Add to this 7 species of Lithistidae (Lyidium, Vetulina, Corallistes, 

 Discodermia) . Finally the authors found 11 species of Hexactinellids, belonging 

 to the genera Hyalonema, Pheronema, Caulophacus, Crateromorpha (?) and Aphro- 

 callistes (?) . Thus Monactinellids show a remarkable preponderance in the 

 number both of genera and species, exactly the reverse from what is known about 

 Cretaceous and Jurassic strata. 



Lendenfeld ( 3 ) believes that in many instances Hinde is wrong in his identifi- 

 cation of the spicules, and puts simply other names. 



According to Topsent ( 2 ) most authors consider Calcareous sponges too 

 distant from the other sponges ; and he therefore does not want to accept the 

 classification in Calcaria and Incalcaria, but divides the Class Porifera into three 

 Sub- classes: Calcarea, Hexactinellida and Dernospongiae. The latter is divided 

 into four orders : Tetractinellida, Carnosa, Monaxonida and Ceratina. On the 

 three expeditions of the Prince of Monaco 167 species were found, 50 of which 

 are new. There were dredged 12 species of Calcaria, but no new ones. Hex- 

 actinellida 13 species (3 new). For Hertivigia a new family (Hertwigiidae) is 

 proposed with the following diagnosis: - - Charpente faite d'hexacts et de diacts 

 soudes par 1'intermediaire de nombreux synapticules. Spicules libres. du paren- 

 chyme: hexacts de deux sortes, dont 1'une est coufinee a la surface. Microscleres 

 caracteristiques: oxyhexasters a rayons en faucilles. Besides H. the author 

 places in this family the genus Traclnjcaulus. - - Tetractinellida: 23 Choristida 

 (5 new) and 6 Lithistida. Carnosa: 3 species. Ceratiua : 1 species. Monaxo- 

 nida: 108 species (about 50 new). The author proposes the following classifica- 

 tion of this order : - - Sub-ordo I : Halichondrina, including the families Homor- 

 rhaphidae, Heterorrhaphidae, Desmacidonidae, and Axinellidae. Sub-ordo II: 

 Spiutharophora. This group is divided into two Sections , Aciculida and Cla- 

 vulida. To the former belong the Epallacidae, Stylocordylidae, and Tethyidae, 

 to the second section the Spirastrellidae, Suberitidae, and Clionidae. On the 

 whole this classification is an attempt to reconciliate the systems of Sollas and 

 of Ridley & Dendy. Of the new genera mentioned in the preliminary account 

 [cf. Bericht f. 1890 Porifera p 3] diagnoses are given, as well as of the new 

 genera Gladocroce, Joyeuxia, Pytheus, Slylostichon, Rhabderemia, Spam'oplion, and 

 Stylmos. 



Delage found that in the flagellated chambers of several sponges there 

 is to be seen a central cell. This cell is perhaps reldment figure qui servirait de 

 centre et d'origine a une substance cimentante rdpandue entre les faces exterieures 

 des collerettes (Sollas' membrane, substance cimentante de Lendenfeld). 



Topsent ( 4 ) mentions 20 sponges from the Red Sea, 4 of which are new. 



Topsent ( 5 ) gives diagnoses of several new sponges from Banyuls : Sanidastrella, 

 Rhaphisia, Leptosia, Hymerhabdia, and Holoxea. 



B. Porifera incalcaria. 



I. Hexactinellida. 

 See, supra p 3, Vosmaer, p 4, Topsent ( 2 ), p 3 ; Hinde & Holmes. 



