Discocerji of a Ses.si/e ('<inulari<( . — Iitiej/einCun. 69 
node. Tlie pyrite in both specimens points to the former ex- 
istence of canals, or at least to an original ditference between 
the material which has been replaced by pyrite and the en- 
closing chitine. There can hardly be any doubt that the cross 
of pyrite represents the basal junction of the marginal grooves 
of the pyramid, and that the little node in the center of the 
base (of. figs. 11 and 17) is the real apex of the pyramid. 
The direct continuance of at least two grooves is exhibited by 
quite a number of remains, e. g., by those reproduced in figs. 
18 and 19, while the original to fig. 20 gives a neat section 
through the four grooves at the entrance of the pyramid into 
the bell. It is evident from the latter fossil that these grooves, 
as already demonstrated in the first article, were originally 
covered by a carbonaceous film and filled with phosphate of 
lime. The supposition is, therefore, not out the way, that 
they may have been free from this filling towards their prox- 
imal ends and could therefore have been filled by pyrite dur- 
ing the process of fossilization. 
The morphology of the whole appendage will be best under- 
stood from a diagrammatic section, as given in fig. 21. The 
apex of the pyramid ((}) is enclosed in a stout central cup 
(b), which, in tiirn, is connected by a thin film (c) with the 
broad basal extension of the exterior bell (a). The latter 
again is fastened to the pyramid a little above the cu]>. 
There can be no doubt that the basal appendage was an or- 
gan of attachment. It is further evident that the latter did 
not amount to a coalescence, but was of a temporary charac- 
ter only; for the not uncommon occurrence of detached spec- 
imens with well-preserved basal appendages (cf. figs. 2 and 4) 
is not consistent with the assumption of a coalescence. The 
apparatus, therefore, cannot be compared to the basal disks, 
such as certain bryozoans have. On the other hand, it is in- 
dicated by the impressions left by the appendages* that their 
inner parts were flexible or even retractable, while the stout 
exterior bell, with its broad, radially striated base, apparently 
served to give stability to the mechanism and to close the in- 
terior tightly from the exterior. 
*Cf. fi^s. 16 and 9, which show the rh:g-like impression (c) of the bell 
to be con8ideraV)ly deeper than that of the wrinkled basal film (c/). 
