I12 JOURNAL AND PROCEEDINGS. 
The assignment of Aulocopina to its proper position in the system 
of sponges is entirely dependent on its skeletal structure. 
The genus is not confined to the single species described by 
Billings, but is widespread in pattern. | Numerous variations within 
the genus have more recently been found, and in the opinion of 
Mr. A. E. Walker, who is versed in these fossils, several fragments ob- 
tained by him indicate that one or more stalked or branching forms 
are to be included, which are of Aolyzoon character. All the speci- 
mens found are weathered out of the rock, but are partially attached 
to or covered with a tenacious material peculiar to the sponge beds. 
The adhering substance consists of fragments of specules and earthy 
matter, which appears to have mixed in with the sponge-flesh of the 
organism at the time of its burial, since which time the present 
adhering material has become a place suitable for the accumulation 
of considerable sub-oxide of iron, and tenacious matter mixed 
with particles of silica. 
In the Museum of the Hamilton Association there are 
several different forms assigned to the genus Aulocopina, (possibly 
correctly referred) some of which are extremely similar to Lospongta 
Billings and some very like the erroneously described sponges found 
in Illinois. | 
Examples of this species do not invariably have the striz in 
ridges on their exterior as referred to; their absence, however, is 
not to be regarded as of specific importance, nor do all oval. 
examples of the species indicate the Osculum as plainly as intimated 
in the specific description. In some specimens no trace of any true 
Osculum can be found until a section is made of them, and being 
globular or ovate the upper cannot be distinguished from the lower 
part of the fossil. The species proper is ‘‘astyloid,” evidently 
sessile, free, and in its lifetime could exist on the sea floor almost 
as well in one position as in another. This species should not be 
regarded as the type of the genus, but as the best species that had 
come to the knowledge of Mr. Billiags. His enumeration of its 
generic character shows plainly the necessity of a better definition. 
Some of the parietal characters are fairly entitled to separation. 
Nov. 25th, 1892. 
