FOSSIL MKDUS.E. 715 



FOSSIL MEDUSAE. 



Fossil medusae, or in many cases fossils supposed to he those of" meduss, have heen 

 described from the lower Cambrian and Devonian, and especially from the Jurassic litho- 

 graphic slates of Bavaria wherein their preservation is so perfect that in some cases, as in 

 Paraphyllttes dtstinctus, they can he classified accurately with relation to living forms. 



Owing to the uncertainty with which we inust regard many of these fossils I have deemed 

 it best to group ihem together and not to attempt the fruitless task of classifying them, except- 

 ing in cases wherein their state of preservation warrants such a procedure. 



A thorough review accompanied by excellent illustrations of all fossil medusae known 

 previous to 1898 is given by Walcott in Monographs U. S. Geological Survey, vol. 30, 1898, 

 and this work should be consulted by all students of the subject, for the account here given 

 does not attempt to present detailed descriptions. 



Medusina radiata Walcott. 



Aitylospotigia radiula, Linnarsson, 1871, Kongl. svensk. Vct.-akad. Handl., vol. 9, No. 7, p. 13, plate 2, figs. 15, 16. 



Medusites rmiintus, Nathorst, 1881, Kongl, svensk. Vet.-akad. Handl., vol. 19, No. I, p. 25, plate 6, figs. I, 2. — ( ?) Pompkckj, 



1896, Jahrbuch, K.-k. geol. Reichsanstalt, Bd. 45, p. 501, taf. 14, fig. 3. 

 Medusina radiata, Walcott, 1898, Monographs U. S. Geol. Surv., vol. 30, p. 56, plate 28, fig. 2. 



This fossil medusa from the lower Cambrian sandstone of Sweden is probably one of the 

 yEquorida; and bears a general resemblance to the genus ZygoJactyla. Bell 40 to 60 mm. wide. 

 Central stomach 25 to 30 mm. wide. 130 to 150 radial-canals which occasionally branch. 

 SubuiTibrella with radiating string-of-pearl-like papillae as in ZygoJactyla. Nathorst describes 

 these papillae as being upon the radial-canals, but to me it seems more probable that thev are 

 interradial as in Zygodactyla. 



Pompeckj's somewhat similar medusa from the middle Cambrian beds of Bohetnia is 

 probably an /Equorea, and not a Zygodactyla. 



Medusina princeps Torell. 



Prololyellia princeps, Torell, 1870, Lunds Universitets Arks-Skrift, 1869, No. 8, p. 10. 



Asiylosponiga radiata, Linnarsson (in part), 1871, Kongl. svensk. Vet.-akad., Handl., Bd. 9, Nr. 7, p. 13, taf. 2, fig. 15. 



Medusites favosus, Nathorst, 1881, Kongl. svensk. Vet.-akad. Handl., Bd. 19, Nr. i, p. 25, taf. 25, taf. 5, fign. 5, 6 (.^). 



Medusites princeps, Matthew, 1890, Trans. Royal Soc. Canada, vol. 8, p. 140. 



Medusina princeps, Walcott, 1898, Monographs U. S. Geol. Surv., vol. 50, p. 54, plate 28, fig. I. 



This fossil from the lower Cambrian of Sweden is of doubtful affinities. Nathorst's 

 conclusion that it is one of the C3aneidae because the exumbrella floor of the stomach exhibits 

 polygonal facets appears to me to be too venturesome, for the radiating furrows of the sub- 

 umbrella resemble the radial-canals of i^quorea. 



Medusina deperdita Walcott. 



Acalepha deperdita, Beyrich, 1849, Zeitschrift deutsch. Geol. Gesell., Bd. I, p. 437, taf. 39, fig. i. 

 Medusites dcperditus, H.AECKEL, 1865, Zeitschrift fur wissen. Zool., Bd. 15, p. 506, taf. 39, fig. I. 

 Medusina deperiia, Walcott, 1898, Monograph U. S. Geol. Surv., voL 30, p. 91, plate 44, fig. i. 



It is possible that this fossil medusa from the Jurassic limestone of Eichstiidt may belong 

 to the genus Cunoctantha, but there are no tentacles and we have only the 8 stomach-pouches 

 upon which to hazard this inference The bell is "o mm. and the diameter through the stomach- 

 pouches 45 mm. wide. 



Paraphyllites distinctus Maas. 



Paraphylliles distinctus, M.vas, 1906, Ncu. Jahrb. Min. Geol., PaKiontol., Bd. 2, p. 90, 4 fign. 



The preservation of this fossil from the Jurassic lithographic slates is so perfect that its 

 affinities with living medusas can be determined. It is therefore described on page 549 in 

 connection with Fnraphyllina to which it is closely related. 



