6 DE. CAEPENTEE'S EESEAECHES ON THE FOEAMIXIFEEA. 



which communicates in like manner by a single passage with the third, as does the third 

 with the fourth ; the fourth chamber, however, communicates by two passages 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 consecu- 

 tive partitions which divide the chambers forming the next half-convolution. Then, 

 however, commences a very remarkable increase ; for whilst in each of the next two 

 partitions there are four passages, the numbers in the four succeeding partitions which 

 divide the chambers completing the second turn are respectively 6, 9, 11, and 14 ; 

 whilst in the last eight partitions which divide the chambers of the outer half-whorl, 

 the numbers of the apertures are respectively 14, 20, 26, 28, 30, 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 first con- 

 volution and a half, it should so rapidly augment from 4 to 48 in the last half-con- 

 volution. 



128. As I have not been fortunate enough to obtain any other than dried 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 

 EHEENBERG, who collected living specimens in his expedition to the Red Sea; and by 

 treating these with dilute acid, he has freed the animal body from its enclosing shell, 

 precisely as I was able to do in the case of Orbitolites. The figure * which he has given 

 of the animal corresponds in every important particular with what an examination of 

 the shell would lead me to expect ; for it represents a series of segments of a generally- 

 homogeneous substance, corresponding in form, dimensions, and connexions with the 

 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 in the 

 positive assertion that no such principal aperture exists at the inner margin of each 

 septum, as would be required to give passage to such a band as is figured by Professor 

 EHRENBEKG. Consequently I can only account for this feature in his delineation 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 familiarity 

 with the Red 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 

 *v Abhandl. der Komgl. Akad. der Wiasenschaft. zu Berlin, 1838. Physik, taf. 2, fig. 1. 



