LOWER CAMBRIAN., 57 
Thus these lamellie seem to be the remnants of a coating which the sponge possessed, 
whereas the fossil for the restis perhaps a mere cast. In their consistency they hardly 
differ from the ordinary sandstone mass. One might rather expect to find, in agree- 
ment with the usual conditions, that such an epidermis existed on the lower side of 
the sponge. It is therefore not impossible that the side which I have described as 
the upper may really be the lower, although on that supposition the mode of forma- 
tion of the fossil would be more difficult to explain. The opening which interrupts the 
ornamentation would in that case be the surface of attachment, and the sponge would 
thus have been attached. I have found no specimen in situ, and thus no conclusion 
can be drawn from the natural position of the fossil. No structure can be distin- 
guished in the interior. Thus the generic position remains uncertain, even if it be 
assumed that the hemispherical side was the lower, and that therefore the sponge was 
free. The species usually differs considerably from the typical species of the genus 
Astylospongia, but it seems still more difficult to unite it with any other of the genera 
above described. In all probability it ought rather to form a genus by itself, but to 
establish such a genus now would be of little advantage, since no definite generic 
characters can be given. 
This species is not uncommon at Lugnas. At times specimens are found lying 
altogether loose. They have been embedded in clay slate which was detached by 
weathering. Others remain fixed in the sandstone slabs, and in such ease ordinarily 
form groups. At Stola I found a stone slab densely studded with individuals of this 
species. A loose specimen I received from Mésseberg. 
Dr. Linnarsson’s reference of the species to the Spongiz was, as noted 
by Dr. Nathorst, opposed by M. Barrande, Prof. G. Lindstrém, and Dr. Ferd. 
Roemer, and was finally given up by Dr. Linnarsson.’ 
Dr. Nathorst, in his memoir of the Cambrian medusz, described this 
species as follows: 
A species probably belonging to the craspedote meduse, family 4. quorid, with 
disk-like umbrella 40™" to 60™™ in diameter; wide mouth, like that of Aquorea or 
Mesonema, taking up about half the transverse section of the body; radial canals 
many, probably 130 to 150, single (or sometimes branching toward the edge); gonads 
with string-of-pearls appearance all along the under side of the radial canals. 
The species is illustrated by a reproduction of photographs of a large, 
finely preserved specimen and a small slab retaining the impression of the 
lower side of several individuals. These certainly appear to be different 
from the form described as Medusites favosus; and it appears that Dr. Lin- 
narsson illustrated two species as the type of M. radiata. His fig. 16 corre- 
sponds to the described type; and fig. 15 is the form taken by Dr. Nathorst 
1 Kongl. svensk. Vet.-Akad. Handl.. Vol. XIX, No. 1, p.6. 
