1886. | POSITION AND CLASSIFICATION OF SPONGES. 579 
3. Familia Rossetuips, F. E. Schulze. 
The dermalia have no centripetal ray. 
Lanuginella, O. Schmidt ; Polylophus, F. E. Schulze ; Rossella, 
Carter ; Acanthascus, Bathydorus, Rhabdocalyptus, Crateromorpha, 
Aulochone, Caulocalyx, and Aulocalyx, F. E. Schulze. 
ii. Tribus Amphidiscophora, F, E. Schulze. 
Amphidiscs in the limiting membranes. Hexaster absent in the 
interior. A basal tuft is always present. The ciliated chambers 
appear as somewhat irregular sac-shaped extensions of the membrana 
reticularis. 
4, Familia HyALONEMATIDA, Gray. 
Numerous pentact pinnule in the dermal and gastral surfaces. 
1. Subfamilia Hyalonematine, F. E. Schulze. 
Calyculate, with a well defined oscula-area on the upper surface. 
Hyalonema, Gray ; Stylocalyz, F. E. Schulze; Pheronema, Leidy ; 
and Poliopogon, Wyville Thomson. 
2. Subfamilia Semperelline, F. E. Schulze. 
Without gastral cavity and terminal oscula-area, with root-tuft. 
Semperella, Gray. 
To this Subordo the fossil families Receptaculitidee and Monakidee 
belong. 
u. Subordo Dictyonina, Zittel. 
The parenchymal hexacts early coalesce in a regular manner, so 
as to form a firm skeleton. 
i. Tribus Uncinataria, F. E. Schulze. 
With uncinates. 
i. Subtribus Clavularia, F. E. Schulze. 
With radially situated clavule. 
1. Familia Farreipa#, F. E. Schulze. 
The skeleton forms a single layer; from the joining points conical 
extensions arise, in a direction vertical to the surface of the network. 
Farrea, Bowerbank. 
2. Subtribus Scopularia, F. E. Schulze. 
With radially situated scopulz. 
2. Familia Euretipa, F. E. Schulze. 
Branched and anastomosing tubes. The skeleton-net forms several 
layers. 
Eurete, Carter ; Periphragella, Marshall; and Lefroyella, Wyville 
Thomson. 
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