Some Recent Graptolitic Literature. — Gurley. 37 
stand in what way the heavy polypary could have been moved. Wave 
-action being excluded ( "the Graptolites were deep-sea dwellers" ) flota- 
tion could only be secured, he argues, through swimming movements of 
the zooids or by the possession of a hydrostatic apparatus. The possi- 
bility of movement by the former means is regarded as very improbable 
in view of the independence of the cells, their opening upon one side 
only, and the form of the stem on the other side. No less improbable, 
he thinks, is the assumption of a hydrostatic apparatus. It is asserted 
that such could only have been the central disk. Herr Jakel rejects the 
possibility of such a view of its function as the cells would necessarily 
have been directed downwards, a condition which, he tells us, has never 
been observed in the analogously constructed living colonies. 
On the other hand, by assuming these organisms to have been fixed we 
can, he thinks, form a "simple and natural picture "of the genus Dicty- 
onema with the-" cell-less net" imbedded in the mud and the cell-bearing 
branches projecting with the cells directed upward. Possibly this may 
possess the merit of simplicity, but the fact is that the "cell-less net " 
has no existence. If Herr Jiikel will consult Brogger's memoir* 
he will find that the branches in Dictyonema are thecaphorous 
along their whole length; although they may apparently lack thecte in 
any portion from unfavorably directed pressure. The central disk is 
also by Herr Jiikel regarded as mud-imbedded. 
The sicula receives little notice. It indeed furnishes opportunity to 
quote Professor Nicholson's Monograph again to the effect that the 
radicle ( sicula) was present certainly in some and probably in all cases. 
We are then told that " when this probably shall have been actually 
made credible through numerous and not as heretofore by 'some cases,' 
I would ask whether this organ may not be regarded as the foundation 
•of the stem and have served for preliminary imbedding until, the lateral 
spreading of the 'cell-less root ' or a broad disk moored it securely." 
•Considering the overwhelming mass of evidence showing the sicula to 
be the embryonic stage, so to speak, of the graptolite, it is only neces- 
sary to remark that in some genera the sicula is so imbedded in the 
substance of the polypary that it could not have been stuck in anything. 
For his next theory the support of Prof. Hall's authority (under date 
of 186.5) is invoked. This time it is a revival of the view that the 
Monograptid^ are fragments of compound forms; another defunct 
hypothesis which, natural enough for the date at which Prof. Hall wrote, 
Jacks the slightest trace of support from later investigations. 
We arrive now at the proposed subdivision of the genus Monograptns. 
We are here reminded very strongly of the methods of securing a change 
of dynasty in vogue in some of the South Sea Islands. When a king 
becomes aged he is told by his son that he in his turn wishes to mount 
the throne. The old monarch acquiesces and a funeral procession is 
formed which escorts him to his grave. Some such custom seems about 
to bo introduced into our midst. With regard to Herr Jakcl's proposition 
to divide the genus Monograptns we have nothing to say. It is not the 
aBroffger, W. C, 1882, Die silur Etagen 2 & 3, im Kristiauiagebiet. 
