50 FOSSIL MEDUS&. 
preserved, and the casts do not even show any trace of its sculpture. We are also left 
in the dark in regard to the position and nature of the organs most important for classi- 
fication, such as the mouth, the anus, ete. Such being the case, it is impossible to 
determine with certainty their place in the system, and their relation to each other, 
all the more because in many cases it can not be decided to what extent the differ- 
ences are to be attributed to the changes to which the casts were subjected after their 
first formation. Such changes readily occurred before the mass hardened by reason 
of pressure or other external agencies, which is rendered evident by the fact that 
most of the specimens are more or less oblique. Nevertheless, these fossils are of 
great interest as the oldest representatives thus far known of their class, and for that 
reason I deemed it incumbent on me to give a description of them, however unsatis- 
factory it necessarily must be. For the reasons given above, their affinities can not 
be made out with any degree of accuracy. Professor Loven is inclined to regard 
them as Cystidee, perhaps related to Agelacrinus, and accordingly I have provision- 
ally given the above name to the form which seems most constant. Its outline is 
either circular or more or less distinctly five- or four-sided, with the corners rounded 
off. One side is of low conical form, sometimes nearly hemispherical. It bears four or 
five radiating ribs, which proceed from the point and extend to near the edge. There 
they are nearly always broken; it is found, however, that they had prolongations 
which extended beyond the edge and formed free arms. A few specimens, which are 
attached to sandstone plates, and one of which is represented in fig. 10, show long, 
barrow arms; still, the specimens are so indistinct that it can not be made out with 
certainty whether they belong to this species. The opposite side for the most part 
appears nearly even, with a slight circular depression in the middle. In one speci- 
men (figs. 8,9) it has an altogether peculiar structure, bearing on the periphery five 
oval, strongly marked elevations, each of which corresponds to one of the radiating 
ribs on the other side. If these are imagined absent, the form will be the usual one. 
Agelacrinus (2) lindstrémi was found by me at Lugnas only, and even there not in 
special abundance. Usually, however, several specimens are found together. They 
are often embedded in clay slate, so that they can be detached. To be able to explain 
this fact, taken together with their nature as casts, it must be assumed that they are 
not altogether complete. Some part of the animal must have risen above the clay 
mud, so that after its dissolution an opening was left through which sand, when it 
began to be deposited, might enter, and one is led to think that the sandstone tube, 
which gradually filled up this opening and connected the casts with the sandstone 
stratum formed above the clay bed containing the casts, was broken off. On the 
specimen collected, however, no trace of such a break can be discovered. Even when 
I found them still embedded in the clay slate nothing touching this subject could ever 
be made out, for the clay slate was always in such condition that when the casts were 
loosened from it it crumbled to pieces, together with the small cavities filled with 
sandstone, in form of arms and the like, connected with the casts. A more accurate 
investigation of the structure of the animal must, therefore, be left to the future, 
together with the explanation of the remarkable difference in the structure of one 
