Jereica polystoma
Roemer 1864
Jereica polystoma is typically cylindrical or club-shaped and may reach considerable height (0.5 meters). It has a smooth outer surface with many tiny pores (different from Stichophyma multiformis). Its top may be more or less truncated, as in the picture, or rounded, with a larger number of oscules located in the center.
The specimen shown in this picture apparently has toppled at some stage and then continued its upright growth. Also many small roots developed subsequently at the underside of the toppled part.
This is an example of Jereica polystoma with a rounded top.
Longitudinal and cross sections of Jereica polystoma.
The pictures show a number of coaxial tubes of the exhalent water system, exiting in the oscules on the top of the sponge. The outer shell of the sponge is made up of numerous radial prosopyles (inhalent water channels conducting water from the ostia to the choanocyte chambers in the interior).
Jereica tuberculosa
Roemer 1864
Jereica tuberculosa is very similar to Jereica polystoma, except for its tuberculate surface. As Schrammen (1910) pointed out, the tuberculate growth forms could be caused by parasites, and in this case J. tuberculosa would not represent an independent species.
Jereica punctata
Goldfuss 1826-33
Jereica punctata has not been reported from Misburg and Höver before. It is pear-shaped and does not reach the height of Jereica polystoma. The internal canalization is analogous to that of Jereica polystoma, but the postica of the exhalent aporhyses are located in a central depression on the apex of the sponge.
The example shown in the picture is a variety called Jereica punctata var. turbo (Schrammen, 1924).
Jereica oligostoma
Schrammen 1910
Jereica oligostoma differs from Jereica polystoma by the concentric bulges, which may be rounded or sharp edged, as in the picture. The number of postica is similar in both Jereica species and hence their names are misleading. This and the next example demonstrate the great variability of Jereica species.
Another peculiar habit of Jereica oligostoma, with several ring-shaped bulges.