No. 395.] REVIEWS OF RECENT LITERATURE. QII 
All the undoubted fossil species are classed with the Discomedusæ, 
and as Haeckel considers this suborder as genetically late in the his- 
tory of the Acraspeda, their presence in the Cambrian indicates that 
the differentiation of the class into orders must have taken place in 
pre-Cambrian time. 
There are seven species known from the Cambrian of the United 
States, Sweden, Esthonia, Russia, and Bohemia. A single species 
has been noted in the Permian of Saxony, and twelve forms have 
been described from the lithographic slates of Bavaria. These 
twenty species, together with two doubtful forms, are described with 
as much completeness of detail as the preservation of the specimens 
will permit. Their treatment, as a whole, furnishes the student with 
a valuable thesaurus of all the available knowledge on the group and 
a wealth of excellent illustrations. 
For a long time the early name of Medusites of Germar (1826) 
was employed as a generic term to include all fossil jellyfish, but as 
the original specimens appear to belong to Lumbricaria, Walcott pro- 
poses the name Medusina to include all species the true generic 
character of which cannot be ascertained. Under this term three 
Cambrian, one Permian, and six Jurassic species are placed, thus 
leaving but ten species sufficiently well preserved to be satisfactorily 
defined and classified. Of these ten species six are from the Jurassic 
of Bavaria and are described under six generic designations. The 
remaining four species are from American Cambrian terranes and 
comprise Broovksella alternata, B. confusa, Laotira cambria, and Dac- 
tyloidites asteroides. The compound nature of Laotira is of unusual 
interest, especially some specimens of Z. cambria and D. asteroides 
that indicate occasional reproduction by means of lateral fission. 
Among recent genera this process is extremely rare. 
The giving to indeterminate and unknown markings, mostly inor- 
ganic, a binomial nomenclature is quite’ as productive scientifically 
as giving generic and specific names to fog and thunder. One such 
term is “ Eophyton,” described in 1868 as a plant with monocotyledon- 
ous affinities. It has since been enriched by a number of species. 
Nathorst was of the opinion that many of these fossils represented 
trails of Meduse. Walcott concurs in this and supplements it by 
proving similar markings to be casts of trails of drifting Algæ in 
shallow water. CEB 
