66 FOSSIL MEDUSAE. 



the medusae 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 medusa?, could be left bv 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 medusa?, 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. 1 It has been 

 suggested that the fossil should be referred to the Alga?. 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. S. Leuckart 2 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. 3 The same specimen is referred to later by Eichwald, 4 who regarded 

 it as a Scutella. He subsequently produced it at a convention at Regens- 

 burg, where Beyrich saw it and described it under the name Acalepha deper- 

 dita. 5 In 1857 Professor Agassiz mentioned in his essay on "Classification" 

 that "Acalepha had been found in the Jurassic limestone of Solenhofen." 6 

 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. 7 In 1865 Professor Haeckel gave a 



'Am. Jour. Sci., Vol. Ill, 1821, pp. 285-287, PI. I. 



2 Ueber die Verbreitung der uebriggebliebenen Reste einer vorweltlichen Schiipfung. Freiberg, 

 1835, p. 12. 



3 Brandt, Ueber fossile Medusen: M<5m. Acad. imp. sci., St. P^tersbourg, 7th series, Vol. XVI, 

 No. 11, p. 1 ; Melanges biolog. tire's du Bull, de l'Acad. St. Petersbourg, Vol. VIII, p. 170. 



••Das herzogliche leuchtenbergische Museum zu Eichstaedt: Augsb. Allg. Zeitung, 1846, No. 218, 

 p. 1740. 



'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. 



■Loc. cit., Vol. Ill, 1860, p. 125. 



