164 Mr. H. J. Carter on the Form and Structure 



oesophagus or siphon. When the shell is removed by acid, the 

 siliceous carapaces of Infusoria which the animal has swallowed 

 may be observed (in Nonionina and Geoponus) as far back even 

 as the last articulation of the alimentary canal. The structure 

 of this canal is not polygastric but simple ; expanded in the arti- 

 culations, and possessed of a single aperture which is situated 

 anteriorly. In Nonionina the articulations are distinct and con- 

 nected by one siphon ; in Geoponus they are multiple, and each 

 set connected by its proper siphon.' 



" Independently of the alimentary canal, a horny brown yel- 

 lowish mass is seen in every articulation of the spire, the first 

 excepted : this, which is granular, Ehrenberg considers to be the 

 ovary. 



" In searching for a purely negative character, Ehrenberg 

 states that it consists in the want of pulsatory vessels ; that while 

 he has always recognized pulsations in the Mollusca and the 

 smallest aggregated or compound Ascidia, he could never do so 

 in Nonionina and Geoponus, the two species of Polythalamia 

 (Foraminifera) which he more particularly examined*.'' — Journ. 

 Bombay Br. As. Soc. vol. iii. pt, 1. p. 158. 



This is all that had been discovered up to the time of my 

 compiling this paper. I had seen the filamentous prolongations 

 myself, and, on dissolving off the shell of a species of Robulina 

 (D'Orbigny), had found a brown mass occupying the chambers 

 (as it then appeared to me) in loops, in the largest or last formed 

 ones, and diminishing posteriorly ; it was also constricted at 

 each end of the loop by the narrow aperture in the septum, and 

 thus beaded, as it were, posteriorly, where there were no longer 

 any loops, but a simple dilatation of the substance of each 

 chamber. I will not now vouch for the complete accuracy of 

 these observations, for they were made on board ship, with a 

 simple lens and under considerable disadvantages ; and other 

 people have not since described the internal substance of the 

 chambers as occurring in loops, nor have I since seen it in this 

 form myself. 



About the time I wrote this paper, MM. Joly and Leymerie 

 were engaged in the microscopical examination of Nummulites, 

 and the results of their investigations were made known through 

 the ' Comptes Rendus ' on the 24th Oct. 1847. Meanwhile too, 

 Dr. Carpenter examined the fossilized remains of Foraminifera 

 generally, and his communication on the subject was read before 

 the Geological Society of London, 2nd May 1849, together with 

 some extracts from Mr. Williamson's description of the animal 

 and shell of Polystomella crispa (Trans. Microscop. Soc. vol. ii. 



* Acad. Roy. des Sc, Berlin, seance de 16 Janvier 1840, and Scientific 

 Memoirs, Parts X. and XI. 



