66 FOSSIL MEDUS. 
the medusz in the lithographic slates were more favorable than were those 
of early Cambrian time at Lugnas, Sweden. The sediment was much finer, 
and hence better calculated to preserve delicate impressions. And other 
favorable conditions must have been present, such as a tidal flat on which 
the medusze could be left by the receding tide and additional sediment of a 
fine character be deposited on the return of the tide. Thus far this combi- 
nation of favorable conditions appears to have been present only in the 
Bavarian and Swedish localities. 
When looking up the literature of the Jurassic fossil medusz, I found 
that it was quite widely scattered and most of it inaccessible to American 
students. 
The first fossil described as a fossil medusa was found near Lexington, 
Kentucky, and named by Rafinesque Trianisites cliffordi." Tt has been 
suggested that the fossil should be referred to the Algze. It certainly does 
not appear to be a medusa. 
According to Dr. Alexander Brandt, the first printed notice of a real 
fossil medusa seems to date back to 1835, when F. 8. Leuckart” noted the 
existence of a fossil medusa from the Solenhofen slates. This was the speci- 
men examined subsequently by Louis Agassiz. In 1845 Frischmann 
exhibited a specimen before the meeting of German naturalists at Nurem- 
berg. The same specimen is referred to later by Eichwald,* who regarded 
it as a Seutella. He subsequently produced it at a convention at Regens- 
burg, where Beyrich saw it and described it under the name Acalepha deper- 
dita® 111857 Professor Agassiz mentioned in his essay on ‘‘Classification” 
that “Acalepha had been found in the Jurassic limestone of Solenhofen.” ° 
In 1860 he wrote that thirty-three years previously his attention had been 
attracted by two slabs of limestone slate from Solenhofen, in the museum 
of the Grand Duke of Baden, upon which a perfect impression of a discoph- 
orous acaleph and its cast was shown.’ In 1865 Professor Haeckel gave a 
1 Am. Jour. Sei., Vol. III, 1821, pp. 285-287, Pl. I. 
2 Ueber die Verbreitung der uebriggebliebenen Reste einer vorweltlichen Schépfung. Freiberg, 
1835, p. 12. 
‘Brandt, Ueber fossile Medusen: Mém. Acad. imp. sci., St. Pétersbourg, 7th series, Vol. XVI, 
No. 11, p. 1; Mélanges biolog. tirés du Bull. de Acad. St. Pétersbourg, Vol. VIII, p. 170. 
‘Das herzogliche leuchtenbergische Museum zu Hichstaedt: Augsb. Allg. Zeitung, 1846, No. 218, 
p. 1740. 
5 Zeitschr. Deutsch. geol. Gesell., Vol. I, 1849, pp. 437-439. 
» Contributions to the Natural History of the United States of America, Vol. I, 1857, pp. 24, 306. 
7 Loe. cit., Vol. III, 1860, p. 125. 
