LOWER CAMBRIAN. 49 
DESCRIPTION OF GENERA AND SPECIES. 
Genus MEDUSINA Walcott. 
Medusites Germar, 1826. Geogn. Deutschland, Vol. LV, 1826, p. 108, Pl. La, figs. 8-10. 
Medusites Haeckel, 1865. Zeitschr. fiir wiss. Zoologie, Vol. XV, p. 515. 
The genus Medusites was proposed by Professor Germar for some 
problematic fossils that were referred to Lumbricaria by Dr. Goldfuss.' 
This appears to be a correct reference, judging from Germar’s figures. 
Medusites is, therefore, a synonym of Lumbricaria; and Medusina is pro- 
posed as a generic term to include all species of fossil medusze whose 
generic characters can not be determined. 
MEDUSINA CosTATA Torell (sp.). 
Pl. XXIX, figs. 1, 2, 3a—b. 
Spatangopsis costata Torell, 1870. Lunds Universitets Ars-Skrift, 1869, No. VIII, 
p. 11. 
Agelacrinus ? lindstrémi Linnarsson, 1871. Kongl. svensk. Vet.-Akad. Handl., vol. 
9, No. 7, p. 11, Pl. I, figs. 6-9; Pl. II, figs. 10-14. 
Medusites lindstrémi Nathorst, 1881. Kongl. svensk. Vet.-Akad. Handl., vol. 19, No. 
1, p. 25, Pl. IV, figs. 1-10; Pl. V, figs. 1-4. 
Medusites lindstrémi Schmidt, 1888. Mém. Acad. imp. sci. St. Pétersbourg, 7th 
series, Vol. XXXVI, No. 2, p. 27, Pl. II, figs. 34, 35. 
Medusites costatus Matthew, 1890. Trans. Royal Soc. Canada, Vol. VIII, Sec. IV, p. 
142. 
Medusites lindstrémi Walcott, 1891. Tenth Ann. Rept. U.S. Geol. Survey, Part I, PI. 
LVI, figs. 1, la-e. 
Original description: 
Infra globosa, supra obtuse conica, costis 5 acutis, ex apice excentrico radian- 
tibus, prope marginem desinentibus. In parte inferiore cujusque are intercostalis 
eminentia fere semiglobosa costas non attingens. Alt. circiter 30™™, lat. 32™™, speci- 
minis depressi prope 50™™, 
Locus: In saxo arenaceo formationis cambrice ad Lugnas et Timmerdala in 
monte Billingen, Vestrogothiz. 
Dr. Torell referred the species with doubt to the Echinodermata. Dr. 
Linnarsson referred it tentatively to the genus Agelacrinus, and described it 
in part as follows: 
These echinoderms are among the most remarkable of the fossils of the Eophyton 
sandstone. They vary greatly in form and size. No part of the shell is ever found 
MON Xxx——4 
