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calcareous skeleton, whose proportionate relation to the size of the 

 soft animal has differed but little from that borne by the siliceo-kera- 

 tose net- work of many sponges to the slimy substance with which they 

 are invested. The attempt to isolate the various portions of 0. adunca, 

 and raise each portion to the rank of an individual animal, even in 

 the limited sense in which we should admit such a distinction in the 

 polypes of a Sertularia or a Gorgonia, appears to me wholly inadmis- 

 sible. If the soft structures of Orbiculina are as devoid of visible 

 organization as are those of our British Foraminifera, and I have 

 very little doubt that such will prove to be the case, the whole ani- 

 mal will be very little raised above the Porifera, only possessing a 

 symmetrical, calcareous skeleton, which is at once both external and 

 internal. In the former respect it of course differs from the ordi- 

 nary forms of Amorphozoa. 



I have recently found some frustules of minute Diatomacece (Cocco- 

 neis) in the interior of Polystomella crispa, which I had not succeeded 

 in doing when the monograph on that species was written : none of 

 these, however, are larger than could have been admitted through 

 the orifices usually designated oral. Their distribution in the inte- 

 rior of the organism fully bears out my previously-published views 

 as to the absence of any specially-located intestinal canal, either in 

 Polystomella, Rotalia, Rosalina, Planorbulina, or the Miliola. I 

 have very little doubt the soft animal will exhibit a like deficiency. 

 Being in all probability a mere gelatinous net-work, interlaced 

 through the meshes of a calcareous one, it is even still less likely to 

 exhibit an alimentary canal, such as M. Ehrenberg thinks he has 

 seen in some recent species, than the symmetrical segments of a 

 Rosalina or a Polystomella. No other observers appear as yet to 

 have detected such a canal amongst the Foraminifera ; consequently 

 it is desirable that zoologists should cease to perpetuate the idea of 

 its existence until some more conclusive evidence respecting it be 

 brought forward. 



