348 PROF. EHRENBERG ON ANIMALS OF THE CHALK 
A quantity of marine sediment, from the island Tjérn in the 
Cattegat, which Bishop Eckstrém of Gothenburg had col- 
lected in order to advance the objects of my pursuit, and for- 
warded to me at Berlin through the kindness of M. von Ber- 
zelius, was surprisingly rich in recent specimens of animals 
of the chalk formation. In this sediment of the North Sea 
were found not only all the siliceous-shelled animalcules of 
the chalk marls already observed at Cuxhaven, but also twelve 
other species which had previously been found in the marls of 
Caltanisetta in Sicily, and Oran in Africa. But most interest- 
ing was the occurrence of the living Grammatophora (Navicula) 
africana (known only as fossil from Oran), together with Gr. 
oceanica, recently obtained from Peru, which tends much to 
weaken the idea that there exist in other parts of the globe 
forms of Infusoria considerably and generically distinct from 
the Kuropzan*. There was also a new genus, a four-sided 
prismatic animalcule, which had been first detected in the chalk 
marls of Oran and Greece, resembling a Staurastrum in external 
form, but distinguished by the presence of a siliceous shell and 
four large apertures at the four corners. This form has been 
distinguished under the name ‘of Amphitetras antediluviana. 
There was also a form quite similar to Dictyocha Speculum, only 
not smooth in its minute cells, but provided with short spines 
or teeth, which I had previously observed in the chalk marls of 
Caltanisetta and Oran, and which I have characterized as Die- 
tyocha aculeata. Lastly, I found in vast numbers a series of 
eight of those species of the genus Actinocyclus which help to 
form the greater mass of the silica in the chalk marls of Oran 
and Caltanisetta, and which are readily and essentially charac- 
terized by the number of their rays; partly such as were only 
recently observed by me in those marls, and partly species 
which have already been noticed with 6, 7, 8, 9, 10, 11, 12, and 
15 rays, which I shall name Actinocyclus biternarius (not senarius, 
which likewise occurred), A. septenarius, octonarius, nonarius, 
denarius, undenarius, bisenarius (not duodenarius), and quinde- 
narius. All these species belong exactly to that division of the 
sira moniliformis is still the only peculiar extra Europzan genus that has been 
accurately examined. 
[* This view is also greatly confirmed by the recent researches of Dr. Cantor; 
he observes, in his remarks on the Flora and Fauna of Chusan, “ that most of 
the forms observed at the island of Lantao, situated in the mouth of Canton 
river, and at Chusan, also inhabit Europe.’’ Annals of Natural History, vol. 
ix. p. 861.—Ep.] 
