PERMIAN. 95 



Medusina circularis Haeckel. 



Medusites circularis Haeckel, 1809. Zeitschr. fiir wiss. Zoologie, Vol. XIX, pp. 556, 561 . 

 Medusites circularis Haeckel, 1880. System iler Medusen, p. 048. 



Medusites circularis Ainmon, 1886. Abhandl. Math.-phys. Classe Kiinigl. 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. 

 PI. XL1V, tig. 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. 048. 

 Medusites porpitinus Amnion, 1886. Abhandl. Math.-phys. Olasse Konigl. bayerischen 



Akad. Wiss., Vol. XV, p. 158. 



The very finegrained 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. Xo 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. 1 



THE PERMIAN. 



Genus MEDUSINA Walcott. 



Medusina atava Pohlig. 



Medusites atavus Pohlig, 1892. Altpermische Saurierfahrten, Fische and Mednsen. 

 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 medusse 

 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 maimer, the characteristic tetrameral symmetry of the medusae. 

 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. 



