Jackcl on OrtJwccras. — Rucdemann. 209 
"It also seems important to me to recall here the fact that 
not only the living octopods, but also decapods like Sepia, hide 
in manifold ways upon or in the bottom, either by piling 
up stones and other foreign bodies upon them, or by stirring 
up with their fins so much sand that their back becomes entire- 
ly hidden. From such conditions to the supposed mode of ex- 
istence of the pnragmoceratites, there seems to me only a short 
step. The firm attachment of Spirula at the bottom will, in 
this connection, find an explanation as a phenomenon of re- 
gression." 
We omit here the remarks upon theses 8-10, interesting as 
they may be, as they refer to belemnites and younger dibranch- 
iates, and are somewhat remote from the major propositions 
of the author. 
The discussion which followed professor Jaekel's remarks 
was, judging from the record, both animated and instructive. 
Space forbids me to give more than meagre notes of the argu- 
ments and objections made. Professor Branco pointed out 
that orthoceratites, belemnites and gomphoceratites are never 
found in a vertical or erect position, while professor Beus- 
hausen mentioned the occurrence of long orthoceratites in 
vertical position in the Oneonta sandstone of New York, an 
occurrence made known by professor Clarke. (N. Y. State 
Mus. bull. No. 39. 1900, pp. 167-171.) Others found it diffi- 
cult to understand how endoceratites often several meters long 
could have been supported upon a delicate apex and that the 
bases had never been found in sediments, such as clay, where 
all firm tissues are as a rule excellently preserved. These 
arguments were met by the declaration, that firm ligaments 
held the lower part of the shell upon the basis, that the vertical 
position of the shell was essentially ciTected bv the air cham- 
bers and that tne latter, after the death of the animal and the 
decay of the basal tissues may have drawn the shells away 
from the bases. 
Specially interesting were the remarks of professor v. Mar- 
tens, whose experience as biologist enabled him to illuminate 
from various sides the problem of the mode of existence of 
Orthoceras. V. jMartens agrees w^ith Jaekel in that the ortho- 
ceratites were not free-swimming or pelagic animals, as these 
have all extremely thin, fragile shells and arc, in all classes of 
