JURASSIC. 67 
description of two fossil medusz, one of which was Beyrich’s Acalepha 
deperdita, which afterwards proved to be specifically identical with the 
specimen mentioned by Agassiz. He also described Medusites antiquus, 
and referred Beyrich’s species to Medusite-, placing, however, the two 
species under the genera Craspedonites (C. deperditus) and Acraspedites (A. 
antiquus).” 
Dr. Haeckel, in 1866, described two additional species from the Solen- 
hofen slates, referring them to the family Rhizostome. The two species 
Rhizostomites admirandus and R. lithographicus are illustrated by two very 
good plates.’ This was followed, in 1870, by the description of several new 
genera and species. These include: Palegina gigantea, Leptobrachites trig- 
onobrachius, Eulithota fasciculata, Medusites quadratus, M. bicinctus, M. stawr- 
ophorus, M. circularis, and M. porpitinus. He also described Rhizostomites 
admirandus H., R. lithographicus H., Acraspedites antiquus H., and Trachyne- 
mites deperditus H.2 In 1871 Dr. Brandt published a memoir of Rhizostomites 
admirandus, R. lithographicus, and Leptobrachites trigonobrachius, illustrating 
the species and giving restorations of the two rhizostomes.* In the same 
year he published an historical review of fossil medusze literature and a 
discussion of Acalepha deperdita Beyrich.? 
Dr. Haeckel returned to the study of the fossil medusze again in 1874, 
and described two new species of Discomedusze under the names Hexarhi- 
sites insignis H. and Semeostomites zitteli H.° 
In 1886 Dr. Ludwig von Ammon published a memoir’ in which he 
reviewed the work of his predecessors on the fossil medusz and gave the 
results of his own studies on some new material from the Jurassic rocks of 
Bavaria. Hexarhizites insignis H. is considered to be a synonym of Rhizos- 
tomites lithographicus, and Leptobrachites trigonobrachius as possibly a laterally 
crushed form of the same species. Leptobrachites giganteus H. is said to 
1Ueber fossile Medusen: Zeitschr. fiir wiss. Zoologie, Vol. XV, 1865, pp. 504-514, Pl. XX XIX. 
2Neues Jahrbuch fiir Min., Geol. und Pal., 1866, pp. 257-292, Pls. V, VI. 
3 Ueber die fossilen Medusen der Jura-Zeit: Zeitschr. fiir wiss. Zoologie, Vol. XIX, 1869, pp. 
538-562, Pls. XL-XLII. 
‘Ueber fossile Medusen: Mém. Acad. imp. sci. St. Pétersbourg, 7th series, Vol. XVI, No. 11, 
1871, pp. 1-28, Pls. I, II. 
° Nachtriigliche Bemerkungen ueber fossile Medusen: Mélanges biolog. tirés du Bull. de l’Acad. 
St. Pétersbourg, Vol. VIII, 1871, pp. 168-180. 
® Ueber eine sechsziihlige fossile Rhizostomee, etc.: Jenaische Zeitschr., Vol. VIII, 1874, pp. 
308-330, Pls. X, XI. 
7 Ueber neue Exemplare von jurassischen Medusen: Abhandl. Math.-phys. Classe Konig]. baye- 
rischen Akad. Wiss., Vol. XV, 1886, pp. 105-168, Pls. I-V. 
