LOFTTJSIA FROM DRlTISn COLrMIlIA. 73 



thou<i:h often somcwliiit flexuons dark lino. Tho "tertiary" in- 

 p;vowths, or juUars, are composed of comparatively larp^c ])!irtioles, 

 though these Hcarcoly ever attain a si^^c of one thousandth of an ineli. 

 Thouf^li rough in outline when examined under a high power, they 

 are well defined and compact-looking at their proximal extremities ; 

 where tlicy arc involved in the spongy growth from tlie roof, they 

 become less definite and occasionally ajjpear almost to vanish before 

 uniting with tlie lamina. 



The expansions of the pillars against the roof, or rafters as they 

 have been called, are much deeper than m ide, and thougli definite 

 and clearly seen in tangential sections of tlie lamina, are generally 

 not distinguishable from the spongy ingrowth in transverse or lon- 

 gitudinal sections. ]}oth the rafters and cancellated ingrowth appear 

 to diher much in texture from, and to be much more transparent 

 than, tho columns. The secondary ingrowths, or septa, are of 

 similar material, and in many cases are scarcely to be distinguished 

 but for tho expansion of tlie pillars upon them. 



Tho separation of tho primary lamina from the subsidiary 

 cancellated growth, said to be common in L. 'persim^ and re])re- 

 sented in plate Ixxix. fig. 2 {op. cit.), has not been observed in any 

 of these specimens, a circumstance probably in connexion witli 

 their smaller size and less complex structure. Many specimens show 

 externally a layer of variable thickness of acervulinO or irregular 

 groAvth. This appears to occur chiefly in those examples which 

 may bo supposed to have attained maturity, and to have fornnd a 

 stronger protecting crust round the delicate fabric of the tost, i'ig, 2 

 (PI. VI.) represents this feature, which does not appear to be found 

 in L. iHrslca. A layer of chambers without any definite external 

 lamina appears to bo formed, and these chambers communicate out- 

 ward, with still less regular openings, and degenerate eventually into 

 a cancellated or spongy mass of calcareous particles, which is gene- 

 rally limited by a firmer and darker outer layer. Smaller Forami- 

 nifera arc occasionally included in the substance of the test of the 

 Loftusia, though much larger than anv of the granular fragments 

 usually composing it. 



In the matrix of some of the specimens are a few examples of a 

 form which, though seen onh* in transparent section, from its pre- 

 cise resemblance in size and shape to that figured by Mr. Brady as 

 Climacammeria antu/xa* in his memoir on Carboniferous and Per- 

 mian Foraminifera, I have no hesitation in referring to this species. 



Mr. Brady says of the genus Loftusia that it would " seem to find 

 a natural place a^ the head of the Arenaceous series of Foraminifera, 

 a position corresponding to AlvcoJina in the Porcellanous group, and 

 FusuUna among the Vitreous forms." It is indeed remarkable to 

 find the Palaeozoic forerunner of the more gigantic Tertiary Loftusia 

 agreeing with it so preciselj^ even in many of the more minute points 

 of structure. The case is analogous to that of the discovery by Mr. 

 Brady in Carboniferous rocks of A^unimulina pristim, which in tho 



Monogr. Palajontograpliicul Society, vol. xxx. p. G8, plate ii. fig. 8. 



