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dense than in our English forms, preserving, when dried, its external 

 contour, as well as being beautifully transparent. 



No trace of minute internal organization, such as a specially located 

 intestinal canal, or ovaries, could be detected in any of these examples. 

 The external membrane was studded in some of the dried specimens 

 with a number of minute papillae, of the nature of which I am as yet 

 in doubt. Neither was I able, in any instance, to discover with cer- 

 tainty the presence of any foreign bodies in their interior, though some 

 very minute siliceous organisms were placed in positions indicating 

 the possibility of their occupying the interior of the segments. 



The latter portions varied considerably in their form in different 

 shells, especially when viewed in their antero-posterior aspects. In 

 all they were more or less arrow-shaped ; but were sometimes narrow 

 and elongated, whilst in others they were more obtusely cuneiform. 

 The lateral processes always projected retrally, but were never in any 

 degree attached to the segment towards which their free extremities 

 pointed. 



The organism appears to commence its existence by forming one 

 single spherical cell (fig. 6, c), as in most of the forms of Foraminifera, 

 however varied may be their subsequent modifications. To this are 

 gradually added a few more cells, which are linked together by single 

 intervening necks (fig. 6, d), as is the case with the matured soft ani- 

 mals of Rolalia, Rosalina, and Nonionina. The cells of Polysto- 

 mella crispa, however, rarely maintain this simple type beyond the 

 first few cells. They soon become compressed and arrow-shaped ; 

 the connecting necks increase in number, and the marginal processes 

 or cul-de-sacs begin to make their appearance. These latter appen- 

 dages also become more numerous, until at length the matured seg- 

 ments exhibit the aspect presented by fig. 7. 



These results necessarily lead us to some conclusions which differ 

 materially from those arrived at by M. Ehrenberg, on the examination 

 of his Geoponus stella-borealis. In the first place, he conceived that 

 each chamber of the calcareous shell contained single segments of a 

 number of distinct animals, packed closely one upon another ; the 

 continuations of which were to be found prolonged through the other 

 chambers, — the different segments of each animal being connected 

 together by single necks, as in that of a Nonionina, with which 

 he distinctly compares each individual soft organism ; of these he 

 imagined he found many in one shell of his Geoponus, which he 

 regarded as a kind of compound polypidom ; and in the description 

 of his figures, PI. 5, d, e,f, and g (Taylor's ' Scientific Memoirs,' vol. 



