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TRANSACTIONS OF THE SECTIONS. 57 
Sorte Remarks on the Structure and Relations of Cornulites, and other allied 
eat ~ Silurian Fossils. By J. W. Sater, A.L.S. 
The anomalous nature of the fossils in question having ‘ed to great diversity of 
opinion with regard to their place in the system, the author endeavours to trace out 
their affinity from the internal structure. The Cornulites serpularius, Schl., ranges 
through the Silurian rocks of Gothland, Britain and North America, and is most 
abundant in the Wenlock limestone. Its general form is that of an elongate, knotted, 
thick tube, four or five inches long, appearing like a pile of conical cups, placed one 
in the other, the highest at the small end of the shell. The interior cast has a similar 
appearance. The shells, in the young state, grow in pairs attached to corals and 
other bodies: they are covered with a thin coat, finely striated lengthwise; beneath 
this the edges of the cups or nodes appear covered with concave pits; two or three 
raised lines run along various portions of the inner surface. 
The step-like form of the nodes or varices gives it some resemblance to the stems 
of Crinoidea, to which family Kichwald and Hisinger have referred it; and Dr. Vol- 
borth of Berlin has published a memoir identifying our fossil with the tapering, 
jointed stems of Echinocrinus, which it imitates in form and in the ornamented 
surface. In ordinary testaceous mollusks, the laminz of growth, and consequently 
the varices, are conical, with their bases towards the aperture of the shell, and it is 
the apparently reversed position in this case which appears to have misled naturalists, 
But in truth the growth is not reversed; a longitudinal section shows that at each 
varix the laminz are more distant than on the sides of the cups, and also bullated 
or puckered up, leaving cells in the interstices ; it is just such a form as would result 
from the periodical advances of an animal with a large inversely conical head in its 
shell. The mantle would corrugate in the space left behind it, and the shelly matter 
grow on this as a mould. Instances of this occur in the septa of Cirrus, Serpula? 
polythalamia, and the large interlaminar spaces in the shells of Ostrea, Spondylus, &c. 
Its analogy with corals, to which a most excellent naturalist, J. D.C. Sowerby, has 
referred it with doubt, seems incomplete: if it be regarded as a single polype, there 
are no internal plates or rays, or if the separate cells be those of polypes, they are 
without ostiolz, or if they had them, they must have opened exteriorly, where they 
are covered by a striated film. On the whole, it bears much more analogy to the 
Serpuline, in the attachment of the young shell and its gregarious habits. 
The other group noticed is that of the Tentaculites of Schlotheim, of equal or 
greater range in the Silurian system, and consisting of several species. They have 
many points in common with Cornulites, but their exterior is more symmetrical; a 
section longitudinally will show the thickened and inverted cup-shaped nodes on the 
cast; but the laminz are not undulated at these parts, and the greater thickness there 
is all that indicates a looser texture ; observations with the microscope will determine 
this point. The unjointed tube sufficiently separates them from the Crinoidea, as 
does also their conical terete form. Schlotheim, who first described both them and 
the Cornulites, refers them to that family, supposing they formed a coronet of brachia. 
Goldfuss has also assigned them to Cyathocrinites pinnatus as auxiliary side-arms, 
It is possible they might be straight mollusca like Dentalium, but neither in their ex- 
terior or internal characters do they resemble that genus; and they have so many 
points in‘common with Cornulites, that, if this be accepted as belonging to the Ser- 
pulina, they must be admitted also as free members of the same family. They are 
certainly never attached; and it would be a curious, though not a solitary fact in 
palzontology, that the earliest forms of a genus should exhibit a complex structure, 
and. a variation from the general type of their successors. Systematic zoologists will 
determine whether the structures indicated claim distinction for the Cornulitide as 
a separate family, a subsection of the Serpuling, and whether they should be divided 
into the free and attached groups. 
Notice of some important additions to the Fossils of the Silurian Rocks. 
be By J. W.Satrer, 4.L.8. 
