MR. H. B. BEADY ON SACCAMMINA CARTERI. 275 



represent a perfect animal equally with the many-chambered shell. 

 Occasionally, though very rarely, a chamber is found with a 

 round imperforate base and a single orifice at its apex, and if 

 this is taken to correspond to the ordinary form of Lagena, the 

 fusiform chambers may be regarded as analogous to the disto- 

 mous varieties of that genus. The moniliform fossils might be 

 compared to the Nodosarice, but that all that have as yet been 

 met with have an aperture at each end of the series of segments, 

 and, for any thing known to the contrary, the test might extend 

 itself indefinitely in either direction. 



The test is composite and arenaceous, the constituent particles 

 being fitted and cemented together so as to give a nearly smooth 

 exterior. The size of the sand-grains and their mode of aggre- 

 gation is a character of some importance amongst the recent 

 Lituolida, but as has been before stated, the process of mine- 

 ralization has obscured the minute structure of the fossil in 

 these particulars. 



The interior of the test is commonly smooth, resembling the 

 recent Saccammina; but it sometimes presents a surface of very 

 short, delicate, labyrinthic, shelly ingrowths, as shown in Plate 

 XI., figs. 3 and 4. This cancellated or labyrinthic structure is 

 often met with amongst the arenaceous Foraminifera, and in 

 some genera it is developed to an enormous extent. 



Here and there a specimen may be found with a sort of cir- 

 cular patch on the surface, which has the appearance of a cica- 

 trix resulting either from the gradual closing-in of an orifice or 

 possibly the reparation of some injury to the shell-wall. These 

 slightly raised concentric markings, apparently deposited regu- 

 larly from without inwards, occurring frequently and with con- 

 siderable uniformity, can scarcely be accidental. The positions 

 in which they are generally noticed, viz., the sides rather than 

 the ends of the segments, is an objection, though possibly not a 

 fatal one, to the supposition that they mark the closure of nor- 

 mal apertures. 



When first investigated, the characters of the fossil seemed 

 sufficiently distinct from those of any known type of Foramini- 

 fera to necessitate the establishment of a new genus for its 



