| OCR Text |
Show 1886.] POSITION AND CLASSIFICATION OF SPONGES. 575 II. Ordo HEXACTINELLIDA, O. Schmidt. Schulze (1369) divides the living Hexactinellida into the two Suborders Lyssacina and Dictyonina of Zittel. In the first, the spicules remain isolated or coalesce secondarily in an irregular manner ; in the second, the main spicules coalesce to begin with in a very regular manner, so as to form a continuous scaffolding. In the first suborder Lyssacina, the families Euplectellidae, Gray, Asconematidae, F. E. Schulze, Rossellidae, F. E. Schulze, and Hyalonematidae, Gray, are placed. The second suborder, Dictyonina, comprises the families Farreidae, Gray, Euretidae, F. E. Schulze, Melittionidae, Zittel, Coscinoporidae, Zittel, and Meandrospongidae, Zittel. To these the fossil families Ventriculitidae, Staurodermidse, Callodictyonidse, Coeloptychidae, Receptaculitidae, and Monakidae must be added. In the classificatory scheme below, Schulze's diagnoses are translated. Ill, Ordo CHONDROSPONGI^l, Lendenfeld. As mentioned above, this Order coincides nearly with Vosmaer's (1550) order Spiculispongiae. I divide it into the two groups, Tetraxonia and Monaxonia. The former comprises the Sponges with tetraxon spicules, Tetractinellids and Lithistids ; and the latter those forms which have monaxon spicules, or which have no spicules at all. Sollas (1453) divides the Tetraxonia into two groups:-Choristida, Sollas, without lithistid sclerites; and Lithistida, Zittel, with lithistid sclerites. In the first group the families Plakinidae, Pachastrellidae, Corticidae, Tetillidae, Theneidae, Stellettidae, and Geodinae are distinguished. Vosmaer (1550) divides the Lithistidae, in accordance with Zittel (1639) and O. Schmidt (1306, 1322), into the families Rhizomori-nidae, Megamorinidae, Anomacladinidae, Tetracladinidae. The Monaxonia comprise the families Suberitidae, Spirastrellidae, Tethydae, and Chondrosidae. The Clavulina and portion of the Oligosilicina of Vosmaer. IV. Ordo CORNACUSPONGIiE. I divide the Cornacuspongiae into the two suborders Halichondrina with, and Ceraospongiae without, proper spicules in the supporting skeleton. The Halichondrina comprise the three families Homorhaphidae, Heterorhaphidae, and Desmacidonidae of Ridley and Dendy (1265, 1266). The Ceraospongiae are divided by me into two groups-Macro-camerae with large, and Microcamerae with small, ciliated chambers. To the former belong the families Aplysillidae and Spongelidae, and to the latter the Spongidae, Aplysinidae, and Hircinidae. After this general view of the Classification of Sponges, I shall proceed to give a " system" of Sponges down to subfamilies, mentioning the principal genera in each group. |
