96 



FOSSIL MEDUS-E. 



the Rhizostomse. The figures in the plate show quite clearly the general 

 form of the parts described by Dr. Pohlig, and I have received, through the 

 courtesy of Dr. Wilhelm Pabst, of the Herzogliches Museum at Gotha, a 

 photograph of a slab containing a number of impressions of the same char- 

 acter. Dr. Pabst also calls my attention to a photograph of a slab from the 

 Upper Rothliegende of Thiiringen, from Tambach in the Duchy of Gotha, 

 containing some impressions which Dr. H. Potonie" has designated Spongi- 

 nopsis dyadika 



A specimen of this species kindly supplied for study by Dr. Pabst 

 shows a smooth outer zone and a confused, apparently lobate central por- 

 tion. The peripheral boundary of this speci- 

 men is quite distinctly double. 



Medusina ? sp. undet. 



Through the courtesy of Dr. H. B. Geinitz, 

 I have received a cast of a form that has been 

 tentatively referred by him to Medusites. It 

 occurs in the Bunter Sandstein of the Upper 

 Trias near Grotenleite (or Crotenleeide), be- 

 tween Gossnitz and Meerane. The cast indi- 

 cates an impression such as might be made 

 by the body of a medusa, but, as Dr. Geinitz 

 says in his letter, the remains are too indistinct to warrant any definite 

 statement regarding them, except that they show some resemblance to 

 forms like "Medusites lindstrdmi." 



INCERT^E SEDIS. 



It is possible that imprints or casts of fossil medusas have been described 

 and figured by authors who have not recognized their true characters. Two 

 have come to my notice, to which I wish to call attention as being worthy 

 of further investigation. One of them is described and illustrated by Dr. 

 H. A. Nicholson as Biithotrephis (! ) radiata. It is a peculiar radiate fossil 

 fn >m the Skiddaw slates ( Ordovician), that suggests the imprint of a medusa ; 

 and it seems desirable to have the specimens studied from this point of view. 

 The figures l recall the appearance of some of the medusas and trails on the 



Fia. 24. — Restoration of Medusina atava. 

 (After Pohlig.) 



1 On the occurrence of plants iu the Skiddaw slates: Geol. Mag., Vol. VI, 1869, PI. XVIII, 

 figs. A. B, ami D. 



