6 DB. CABPBNTEB’S EBSEABCHES ON THE EOEAMEf-TEEBA. 
which communicates in like manner by a single passage with the third, as does ‘'“'i 
with the fourth; the fourth chamber, however, commumcates by tooyJKSs®?® with the 
fifth, as does the fifth with the sixth, and the sixth with the seventh. In the septum 
between the seventh and eighth, with which the second whorl may be considered as 
commencing, there are three apertures; and this number continues for the four co^cu- 
tive partitions which divide the chambers forming the next half-convolution. 'Diot, 
however, commences a very remarkable increase; for whilst m each of the next o 
partitions there axe four passages, the numbers m the four succeeding partitions w c 
divide the chambers completing the second turn are respectively 6, 9, 11, and 1 ; 
whilst in the last eight partitions which divide the chambers of ’ 
the numbers of the apertures are respectively 14, 20, 26, 28, SO, 35, 44, and 48. The 
average distance of the apertures from each other remains nearly the same throughout , 
so that their number pretty closely corresponds with, and may be taken to represent, 
the length of the septal plane which they traverse in each case; and it is not a little 
remarkable, that whilst this number should only increase from 1 to 4 in the &st con- 
volution and a half, it should so rapidly augment fiom 4 to 48 m the last half-con- 
128 As I have not been fortunate enough to obtain any other than dned specimens 
of this organism, I have not had the opportunity of examining the structure and arrange- 
ment of its soft parts. Such an opportunity, however, has presented itself to Professor 
Eheenbeeg, who collected living specimens in his expedition to the Bed Sea ; and by 
treating these with dilute acid, he has freed the animal body from its enclosmg sheU, 
precisely as I was able to do in the case of OrUtoBes. The figure^ which he has given 
of the animal corresponds in every important particular with what an examination o 
the shell would lead me to expect; for it represents a series of segments of a generaUy- 
homogeneous substance, corresponding in form, dimensions, and connexions with t e 
successive chambers of Fig. I. The only departure that I can discover from what I 
should myself have anticipated, lies in this-that the successive segments are connected 
along the inner margin of the convolutions by a band much broader and thicker than the 
threads which pass between other parts of the segments; so that this band would seem 
to establish a principal connexion, to which the other threads might be considered as 
secondary. Now after a very careful examination both of the septal planes of numerous 
specimens, and of sections taken in the direction of Fig. I, I feel myself justified m the 
positive assertion that no such principal aperture exists at the inner margm of eac 
septum, as would be required to give passage to such a band as is figured by Professor 
Fheenbeeg. Consequently I can only account for this feature in his delineaUon of the 
animal (the idea of a difference in the conformation of the shell being negatived by the 
precise correspondence between his figures of it and my own, as well as by my famiharity 
with the Ked Sea type of Peneroplis), by supposing that, like some of his other figures, 
it rather represents his idea of the structure of the animal, than what he actually saw in 
* Abhandl. der Konigl. Akad. der Wissenseiiaft. zu Berlin, 1838. Physik, taf. 2, fig. 1. 
