Carboniferous Foraminifera. Bij Bev. W. Hoivehin. 541 



E. ammonoides there is the same exposure of the inner whorls by the 

 only slightly embracing character of the test, but its minute size and 

 the number of its convolutions and septal divisions at once distinguish 

 it from the present species. This departure from the normal character 

 of the genus, shown by E. eonsjncua, is not likely to have arisen from 

 starved conditions as some of the individuals attain a larger size, 

 exceeding those of E. Boivmani, whilst the beds in which they occur 

 are somewhat rich in Foraminifera. 



Distribution. — Eare in the " J " Limestone of the Tipalt, and in 

 a limestone, low in the series, situated in a burn between The Banks 

 and Lannercost, occurring at three horizons in the limestone, in one 

 of which it is moderately common. 



Endotliyra eircumpUcata, sp. no v. Plate VIII. figs. 10, 11. 



Test free, subglobular, irregularly spiral, embracing ; composed of 

 three or more convolutions, which, instead of following the same plane 

 of growth throughout, become twisted, so that the later convolutions 

 are formed more or less at right angles to the plane of the earlier 

 segments. Segments numerous, and in their later growths enlarging 

 rapidly and becoming ventricose. Later chambers subdivided near their 

 umbilical margins by transverse septa. Septal divisions marked 

 externally either by depressed lines or slight limbation. Test plicate. 

 Exterior surface smooth; white or reddish-white. Texture finely 

 arenaceous, and in some cases (?) perforate. The final segment has a 

 protruding lip forming its convex or outer margin, with a correspond- 

 ing hp or ridge transverse to the peripheral margin and parallel to 

 the inner margin of the septal plane. Aperture distinct, oval. 

 Diameter 1/25 in. 



This striking variety exhibits an extreme of inequilateral growth. 

 In its large size and globose form it somewhat resembles Endothijra 

 crassa. The latter includes the " nearly symmetrical," large, globose 

 Endothyrse of the Carboniferous rocks, whilst E. circumj)licata is 

 extremely unsymmetrical, and from this cause exhibits considerable 

 divergence in internal structure from its more equilateral congeners. 

 The umbilical axis is not unfrequently shifted in position by the 

 inequilateral plan of growth to the peripheral margin. Transparent 

 sections show in many instances a remarkable confusion in the 

 arrangement of the earlier chambers with successive foldings, amount- 

 ing in some cases to two, three, or four plications of the shell 

 substance ; and in the expanded chambers of the final whorl, transverse 

 septa, giving rise to small chamberlets, near the umbilical margins 

 of the terminal segments. The last segment is sometimes much 

 contracted by vertical compression towards the aperture, taking the 

 form of a slit which, with its pouting margins and great obliquity of 

 the septal plane, gives the shell a very grotesque appearance. The 

 shelly investment, consequent upon the laminated construction of the 

 test, is very stout in comparison with the other Endothyrse, especially 

 in its earlier convolutions, and has a clear, smooth, and sometimes 



