72 HALKYARD, Fossil Foraminifera of the Blue Marl 



(A very extensive series of specimens showing all stages 

 of growth from the typical N. pauperata of Orbigny's Vienna 

 Monograph, up to specimens in which the later cnambers are 

 separated by a distinct neck.) 



152. Nodosaria (Dentalina) pauperata, d'Orbigny. 



var. bulbosa, nov. 

 PI. IV, figs, io-ii. 



Test smooth, consisting of about twelve segments, sutures 

 flush, excepting the last one or two which are slightly depressed. 

 The initial extremity of the shell pointed and increasing 

 in width rapidly, afterwards contracting so that the first five 

 chambers have together a rhomboidal contour which merges 

 into the gradually tapering growth seen in the type. Length 

 1.4 to 2.35 mm. 



This stout form is frequent in the Biarritz Marls, and is 

 always easily recognised as, besides its form, its texture is quite 

 different from the specimens of D. pauperata found in the same 

 Gatherings, being apparently more compact. 



Costa in his paper on the fossil Foraminifera of the Tertiary 

 Marl of Messina figured a species under the name of Vaginulina 

 clavata which seems to be a closely allied form to the one now 

 under discussion. The initial end of Costa's shell, however, is 

 globular and only consists of one chamber. 



(The peculiar bulbous form of the initial portion of the 

 shell is very characteristic, but varies to so great an extent that 

 it is hardly reliable even as a varietal distinction. In extreme 

 cases it forms quite a striking feature. The structure of the 

 shell wall appears to be much thicker than in the Biarritz speci- 

 mens of N . pauperata, and identical with the Biarritz N . ver- 

 neuili, with which the variety is perhaps more nearly allied.) 



153. Nodosaria (Dental?:na) pauperata, d'Orbigny. 



var. crassisepta, nov. 

 PI. IV, figs. 12, 13. 



Test elongate, earlier portion parallel-sided, later portion; 

 consisting of globular chambers, sutures limbate. Length, 2.4 

 to 5.0 mm. 



This form, which it has been thought necessary to describe 

 under a new varietal name, is rare. If deprived of its sutural 

 limbation it closely resembles the type and its more closely 

 connected variations; a comparison of figs. 12 and 9, and of 

 fig. 1 3 with fig. 14 will be sufficient to prove this point. 



