PERMIAN. 95 
MEDUSINA CIRCULARIS Haeckel. 
Medusites circularis Haeckel, 1869. Zeitschr. fiir wiss. Zoologie, Vol. XTX, pp. 556, 561. 
Medusites circularis Haeckel, 1880. System der Medusen, p. 648. 
Medusites circularis Ammon, 1886. Abhandl. Math.-phys. Classe Kénigl. bayerischen 
Akad. Wiss., Vol. XV, p. 158. 
This is only a medusa impression, in which nothing can be recognized 
besides a sharply defined outline. 
MEDUSINA PORPITINA Haeckel. 
Pl. XLIV, fig. 3. 
Medusites porpitinus Haeckel, 1869. Zeitschr. fiir wiss. Zoologie, Vol. XIX, pp. 556, 
561, Pl. XLII, fig. 5. 
Medusites porpitinus Haeckel,1880. System der Medusen, p. 648. 
Medusites porpitinus Ammon, 1886. Abhandl. Math.-phys. Classe Konig]. bayerischen 
Akad. Wiss., Vol. XV, p. 158. 
The very fine-grained slab shows a quite regular circle, which, by the dark, 
greenish-black coloring of the whole disk surface, stands out strongly against the 
yellow-white stone. 
The dark zone is circumscribed by a bright one, which shows on one side a rather 
wide dark contour. Inside the dark mid-field can be seen several obscure concentric 
circles. No radial markings are shown. The exceptionally clear and sharp definition 
of the circles, in connection with the dark coloring and the corresponding size, leads 
to the supposition that here possibly are the impressions of a fossil Porpita.! 
THE PERMIAN. 
Genus MEDUSINA Walcott. 
MEDUSINA ATAVA Poblig. 
Medusites atavus Pohlig, 1892. Altpermische Saurierfihrten, Fische und Medusen. 
Festschrift zum siebenzigsten Geburtstage Rudolf Leuckarts; Leipzig, p. 64, 
Pl. VII, figs. 2 and 5, 1 fig. in text. 
The accompanying figure (fig. 24, p. 96) shows Dr. Pohlig’s restoration 
of this species, as perfect as he could make it from the material at hand. 
He states that it is possible to distinguish in the impressions of the medusze 
the narrow inner and broad outer ring fields and, in one specimen, traces of 
concentric muscular bands. In the mid-field there is shown, in a somewhat 
indistinct manner, the characteristic tetrameral symmetry of the medusee. 
It is concluded that nothing can be determined as to the exact systematic 
position of the form, except that it does not appear possible to refer it to 
1 Zeitschr, fiir wiss. Zoologie, Vol. XIX, 1869, p. 556. 
