576 DR. R. VON LENDENFELD ON THE SYSTEMATIC [Dec. 21, 
Classis SPONGIAS, auctorum. 
Ccelenterata with branching canal-system, the organs of which 
are developed from cells of the mesoglcea or primary mesoderm. 
With simple epithelia, with entodermal collar-cells, and without 
movable appendages and enidoblasts. 
I. Subclassis CALCAREA, Grant. 
Sponges with a skeleton composed of calcareous spicules. 
I. Ordo CALCISPONGILA, Blainville. 
The only order, with the characters of the subclass. 
1. Subordo Homoca@ a, Poldjaeff, emend. 
The entodermal epithelium consists exclusively of collar-cells. 
1. Familia Asconip#, Hickel. 
Simple sac-shaped gastral cavity with smooth surface. 
Leucosolenia, Poléjaeff, Ascetta, Ascissa, Ascilla, Ascaltis, Ascor- 
tis, Asculmis, Ascandra, Hackel. 
2. Familia HomopERMID#, Lendenfeld. 
The gastral cavity forms cecal outgrowths, which resemble the 
tubes of Syconidee. 
Ascaltis canariensis, Hiickel, Ascaltis lamarckii, Hickel, and 
Homoderma sycandra, Lendenfeld. 
3. Familia LEucorsip#, Lendenfeld. 
A colony of Ascon-persons which are imbedded in the thick 
mesogloea. There are narrow inhalant pores and wider exhalant 
ones. The latter lead into a pseudogaster. 
Leucopsis, Lendenfeld, and some species of Psewdonardorus-forms 
11. Subordo HeTEROCGLA, Poléjaeff, emend. 
The entodermal epithelium is differentiated into collar-cells, 
which are found in the walls of the ciliated chambers only, and into 
flat pavement-cells, which clothe the walls of the exkalaut canals and 
gastral cavity. 
4. Familia Syconip&, Hiickel. 
With regular, radially disposed cylindrical ciliated chambers, which 
open direct into the sac-shaped gastral cavity. 
1. Subfamilia Syconine, Lendenfeld. 
The unbranched ciliated chambers remain isolated in their distal 
part. 
Sycon, Poléjaeff, the subgenera of Hickel’s Syconide which ter- 
minate with the syllable ‘‘aga.” I divide this subfamily according 
to Hickel’s scheme into the seven genera Sycetta, Sycissa, Sycilla, 
Sycaltis, Sycortis, Syculmis, and Sycandra. 
