a new Genus of Foramlnifera. 341 



that this Is the usual order of growth ; and as, in the only two 

 instances I have seen of segments having the central pillar in- 

 complete, the portion formed was attached to the inner surface 

 of the apex of the enveloping chamber, I am disposed to think 

 that, as a rule, this portion of the shell is built up on an ento- 

 solenian plan. It occasionally happens (as in fig. 5) that, on 

 breaking a shell, the central column remains attached to the 

 inner chamber, leaving the outer one at its point of union ; but 

 this is quite an exceptional case ; for in a very large majority 

 of instances the fracture takes place at the opposite extremity. 

 On the other hand, the tendency to entosolenian growth is 

 evinced strikingly in the somewhat anomalous condition of the 

 first and second chambers of a large specimen shown in fig. 11, 

 in which the primordial chamber, containing nothing requiring 

 support, has a rudimentary tongue-like extension of shell- 

 substance from the interior apex. It may be noted, also, that 

 Signor Seguenza figures one of his varieties without any ex- 

 ternal tube. I suspect, therefore, that, having found in one or 

 two instances an ectosolenic tube arising from the breaking- 

 away of an enveloping chamber, the conclusion has been drawn 

 without further investigation that specimens not presenting 

 this outgrowth were imperfect. I speak with considerable 

 reservation, as none of the specimens which have fallen into 

 my hands had an ectosolenian neck, or indeed any evidence 

 that such had ever existed. 



But, recognizing the fact that the central column is not the 

 countei-part of the produced septal orifice seen in many Nodo- 

 sarincB^ in other words, that it is not a stoloniferous tube, we 

 have still to find how communication between the chambers is 

 kept up — a matter of greater difficulty than at first sight ap- 

 pears, on account of the extreme brittleness and delicate tex- 

 ture of the shell. The condition shown in fig. 11, being in 

 other respects monstrous, is of little value as an indication that 

 the septal orifice may occur at the summit of the central co- 

 lumn ; nor is it needful to dwell upon it, inasmuch as I have 

 never seen another example with similar characters. The 

 usual form of the aperture is that of a curved slit, either entire or 

 bridged over here and there, situate at a little distance from the 



lie only two perfect specimens which I have left are almost 

 exactly alike in the aspect of the exterior aperture ; and fig. 8, 

 drawn from one of them, would answer equally well for either. 

 The projecting tongue of shell-substance in the centre is some- 

 what raised, and has a valve-like appearance on being viewed 

 more laterally. In figures 9 & 10 the septal orifices of inner 

 chambers are shown, one of them with, the other without, the 



