70 FOSSIL MEDUS 4. 
Dr. Ammon’s? classification of the fossil medusze from the Jurassic is 
as follows: 
CRASPEDOT# Gegenbaur. (Not yet proved beyond doubt to exist fossil.) 
ACRASPED Gegenbaur. 
Order DISCOMEDUS% Haeckel. 
1. Suborder CaAnNostoma Haeckel. (Not known.) 
2. Suborder SEMosTOoM# L, Agassiz. 
Family Lithosemeide Haeckel. (Fossil.) 
(1) Semzeostomites zitteli Haeckel. 
Family Hulithotide Haeckel. (Fossil.) 
(2) Bulithota fasciculata Haeckel. 
Family (?) Pelagide Gegenbaur. 
(3) Acraspedites antiquus Haeckel. 
3. Suborder Ru1zostomzs Cuvier. 
Family Lithorhizostomee vy. Ammon. (Fossil.) 
(4) Rhizostomites admirandus Haeckel. 
(5) Rhizostomites lithographicus Haeckel. 
Hewarhizites insignis is only the six-rayed form of Rhizostomites 
lithographicus. It may belong to the same family or to the 
family of the Crambessidie (Subfamily Leptobrachidi). 
(6) Leptobrachites trigonobrachius Haeckel. 
MEDUS2Z OF UNCERTAIN POSITION. 
(7) Medusites deperditus Beyrich. 
(8) Medusites quadratus Haeckel. 
(9) Medusites bicinctus Haeckel. 
(10) Medusites staurophorus Haeckel. 
(11) Medusites circularis Haeckel. 
(12) Medusites porpitinus Haeckel. 
DESCRIPTION OF GENERA AND SPECIES. 
Suborder SEMOSTOME L. Agassiz. 
Family LITHOSEM 4 IDA Haeckel. 
Genus SEM-EZOSTOMITES Haeckel. 
SEMAOSTOMITES ZITTELI Haeckel. 
PIG ROOD ies AE 
Semceostomites zitteli Haeckel, 1874. Jenaische Zeitschr., Vol. VIII, pp. 323-329, Pl. XI. 
Semcostomites zitteli Heckel, 1880. System der Medusen, p. 647. 
Semceostomites zitteli Ammon, 1886. Abhand]. Math.-phys. Classe K6énigl. bayerischen 
Akad. Wiss., Vol. XV, p. 157. 
1 Abhandl. Math.-phys. Classe Kénigl. bayerischen Akad. Wiss., Vol. XV, 1886, pp. 157-158. 
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