FOSSIL MEDUSA. 717 



subumbrella a wide marginal ling-muscle, an intermediate zone of i6 feathered arcades as in 

 Casstopca, and an inner zone of ring-muscles around the central stomach. 



At the bell-margin there appear to be numerous thickly set, short, branched, tree-like 

 tentacles. The mouth-parrs are lost. Maas studied 5 imperfect specimens of this remarkable 

 medusa which appears to be distinguished from all other Sc\ phomeduss by its branched 

 marginal tentacles. His best preserved specimen was 300 mm. wide. 



Genus MEDUSINA Walcott, 1898. 

 Medusina, Walcott, 1S98, Monograph U. S. Geol. Surv., vol. 30, p. 49. 



Walcott proposes the name Medusina to designate all fossil medusa who.se generic char- 

 acters can not be determined. 



Among the most obscure are M. quaJrata, M. biciticta, M. stciuropliorti, M. circularis, 

 and M. porpitina from the Jurassic lithographic limestone of Bavaria, and M . atava from the 

 Permian. All of these are well described by Walcott, loc. cit., pp. 93 to 96. Beyond the fact 

 that these fossils are apparently medusae not much can be said of them, and in most cases we 

 can not be certain as to whether they are Scyphomedusa; or Hjdromedusae. 



Medusina costata Walcott. 



o 



Spatangopns costata, Torrell, 1870, Lunds Universitets Ars-Skrift, 1869, No. 8, p. ii. 



Agelacrinus lindnromi, LiNHARssoN, 1871, Kongl. svensk. Vet.-akad.Handl., Bd.9, Nr. 7, p. ii,taf. i,fign.6-7,taf. 2, fign. 10-14. 

 Medusiies Unditromi, Schmidt, 18SS, Mem. Acad. Imp.Sci.St.Petersbourg, ser. 7, tome 36, p. 27, pjanchc 2, figs. 34, 35. -Wal- 

 cott, 1891, Tenth Ann. Report, U. S. Geol. Surv., Part I, plate 56, figs. i-ic. 

 Medusites costatits, Matthew, 1890, Trans. Royal Soc. Canada, vol. 8, p. 142. 

 Medusina cosiaia, Walcott, 1S98, Monographs, U. S. Geol. Surv., vol. 30, p. 49, plates 29, 30. 



This fossil from the lower Cambrian sandstone of Sweden, at Lugnas and Timmerdala 

 in Mount Billingen, is probably an Awellia. The best description is presented by Walcott. 



Medusina geryonides Huene. 



Medusina geryoiiides, Huene, 1901, Neues Jahrbuch fiir Mineralogie Geol.und Palaeoiitol., Bd. i, p. i, taf. i,fign. 1,2. — Fuchs, 

 1901, Centralblatt fiir Mineral. Geol. und Palaeontol., Jahrg. 1901, p. 166. 



This fossil medusa is from the Murchison sandstone of Wiesensteig in Wiirtembiirg. It 

 is about 28 to 30 mm. in diameter. In the center there is a crater-like elevation with an irreg- 

 ular, flat, 6-sided knob at its middle. Surrounding this crater-shaped center there is a zone of 

 12 radiating concavities, the deepest being 2.5 mm. deep. Huene suggests that this medusa 

 ma}' have been related to the Geryonidae, but this is wholly problematical, and it appears to 

 me that it might equally well be a cast of Brooksella. Fuchs casts doubt upon its being a 

 fossil medusa. 



Laotira cambria Walcott. 



Laotira cambria, Walcott, 1896, Proc. U. S. Nat. Mus., vol. 18, p. 613, plate 32, figs. 1-8; 1898, Monographs V. S. Geol. Surv., 

 vol. 30, p. 32, plates 5-19, 21-23. 



This is a fossil from the middle Cambrian shale of Coosa Valley, -A^labama, and is supposed 

 to be that of a medusa. It is a remarkably variable form and quite distinct from any living 

 medusa. It probably reproduced by fission as does Gastroblasta. 



Walcott defines it as Discomedusae with a lobate umbrella with 4 to 12 lobes in simple 

 forms and with a large number in the compound forms. No tentacles and no central mouth- 

 openings in the adult. A simple radial-canal in each lobe of the umbrella and in the inter- 

 radii. Oral arms represented by interradial lobes attached to the central axis and to the central 

 lobes. Described in full detail by Walcott, 1898. It shows a tendency to intergrade in its 

 simplest forms with Brooksella eonfusa from the same formation. 



Dactyloidites asteroides Walcott. 



Buthoirephis (?) asteroides, Fitch, 1850, Trans. New York State Agricult. Soc, vol. 9, p. 863. 



Dact\loidiies bulbosus, Hall, 1886, 39th Ann. Report State Museum Nat. Hist. New York, p. 160, plate 11, figs, i, 2. 

 Dactyloidites asteroides, Walcott, 1891, loth Ann. Report U. S. Geol. Surv., Part i, p. 605, plates 57, 58, fig. 61; 1898, Mono- 

 graphs U. S. Geol. Surv., vol. 30, p. 41, plates 24-28. 



This fossil is from the lower Cambrian terrane of Eastern New York at Penrh\n Quarry, 

 Middle Branville, Washington County, and from St. Albans, Vermont. It is an irregular, 



