FOSSIL MKDUSjE. 715 



FOSSIL MEDUSAE. 



Fossil medusae, or in many cases fossils supposed to be those of medusae, have been 

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

 graphic slates of Bavaria wherein their preservation is so perttct that in sonic cases, as in 

 Paraphyllitei distinctus, they can he classified accurately with relation to living forms. 



Owing to the uncertainty with which we must regard many ot these fossils I have deemed 

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

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



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

 previous to 1898 is given by Walcott in Monographs U. S. (jeological Sunev, vol. 30, 1898, 

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

 does not attempt to present detailed descriptions. 



Medusina radiata Walcott. 



Aitylospongia radiata, LlNNARSSOH, 1871, Kongl. svensk. Vet.-akad. H.mdl., vol. }, No. 7, p. 15, plate ;. figs. 15, 16. 



MeJusites radiums, NATIIORST, iXSi, Kongl. svcnsk. Vet.-akad. Handl., vol. HI. No. r. i ;-. pl.iii- d. figs, i, 2. (?)Po\ir>. M. 



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

 Medusina radiata, WAI.COTT, 1898, Monographs U. S. Geol. Sun"., vol. 30, p. 56, plate 28, fig. 2. 



This fossil medusa from the lower Cambrian sandstone of Sweden is probahh mie ot the 

 ./Equoridae and bears a general resemblance to the genus lygodactyla. Hell 40 to 60 mm. wide. 

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

 Subumbrella with radiating stnng-ot-pearl-hke papillae as in lygodactyla. Nathorst describes 

 these papilla? 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 trom the middle Cambrian beds ot Bohemia is 

 probably an jEquorea, anJ not a ZygoJactyla. 



Medusina princeps Torell. 



Protohellia princeps, TORF.LL, 1870, Lunds Universitets Arks-Skrift, 1869, No. 8, p. 10. 



Aa\losponiga radiata, LI.NS*RSSO\ (in part), 1871, Kongl. svensk. Vct.-akad., Hand]., lid. i), \r. 7, p. 13, taf. 2, fig. 15. 



Medusita jtrcoun, NATHORST, 1881, Kongl. svensk. Vet.-akad. Handl., Bd. 19, Nr. i, p. 25, taf. 25, taf. 5, fign. 5, 6 ( ?). 



Mrjufitts princeps, \\\\ now, 1890, Trans. Royal Soc. Canada, vol. 8, p. 140. 



Medusina princeps, WALCOTT, 1898, Monographs U. S. Gcol. Surv., vol. 30, 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 Cyaneidas 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 /Equorea. 



Medusina deperdita Walcott. 



Acatepha deperdita, BEYRK-II, 1X41), X.eitschrift dcutsch. Gcol. Gcscll., Bd. I, p. 437, taf. 39, fig. i. 

 Medusiies deperdiius, HAECKF.L, 1865, Zcitschrift fiir wissen. Zool., Bd. 15, p. 506, taf. 39, fig. i. 

 Medusina deperiiii, \\.\u 01 r, i i . '.1 r.iph 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 S stomach-pouches 

 upon which to hazard this inference The bell is 70 mm. and the diameter through the stomach- 

 pouches 45 mm. wide. 



Paraphyllites distinctus Maas. 

 Paraphyllites distinclus, MAAS, 1906, Neu. Jalirh. Min. Gcol., Palaontol., Bd. 2, p. 90, 4 fign. 



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

 affinities with living medusz can be determined. It is therefore described on page 541) in 

 connection with Paraphyllina to which it is closely related. 



