234 Description of new Lower Silurian Sponges. — Ulrich. 
mind that so little is known of palaeozoic sponges (Lower Sil- 
urian ones in particular) that almost any contribution to our 
knowledge of them is welcome. The imperfections will prove 
the most serious to the systematist, but for the needs of the 
collector and of those who desire to use these fossils as pal- 
eontological evidence in the determination of strata, it is be- 
lieved these descriptions will suffice, temporarily. The sys- 
tematist also should not forget that among Silurian sponges 
the minute characters upon which his classification is founded 
are so seldom preserved in a recognizable condition that often 
the heart grows weary waiting for the resurrection of the spec- 
imens which, if placed in the proper hands, might be made 
to throw light into the dark recesses of our classifications. It 
is almost needless for me to say that had such specimens been 
at my command I would most surely have fulfilled all the re- 
quirements of scientific publication by describing and figuring 
their minute characters in detail. To offer illustrations now, 
when the structure is only conjectured, might serve but to 
mislead. 
The amateur and mere collector rarely searches for unnamed 
fossils, especially if they belong to so unprepossessing a class 
as the sponges. He must have a name for his specimens or 
they go into his unclassified drawer which too frequently 
merges into his trash box. And how often does not that 
''trash box" contain the very specimen for which we have 
searched so diligently. 
It is, therefore, partly to satisfy and incite him, partly to 
make these fossils available for stratigraphical determination, 
and partly my desire to add a little to the literature of a sub- 
ject so generally shunned by American paleontologists that in- 
duces me to present the following. 
A few remarks upon the systematic position of the proposed 
new genera may prove of value. 
The new genus Rauffella, named in honor of Dr. H. Rauff, 
the distinguished collaborator of Dr. Karl Zittel on fossil 
sponges, is proposed for the reception of two remarkable 
sponges. At first I believed their spicules to be of only the 
uniaxial type and the genus probably a member of the 
MonactinellidoB. A later study,however, proved the results of 
the first to be erroneous, and that, instead of being of the uni- 
axial type, the spicules of the outer layer at any rate are really 
