232 Messrs. W. K. Parker and T. R. Jones on the 



The following four are "sinuate" in the growth of the alar 

 prolongations of their chambers : N. Sismondi (granulate), 

 N. Vemeuili (granulate), N. obtuso, and N. perforata (granulate). 

 The last-mentioned shows a "radiate" arrangement of the septa 

 in its young state — a condition obtaining probably in the other 

 three, as well as in N. Brongniarti (granulate), N. Defrancei 

 (granulate), N. Meneghinii (granulate), N. Deshayesi (granulate), 

 and N. Bellardii (granulate), which appear to belong to the same 

 group of stout, well -grown, medium-sized Nummulina. N. Me- 

 neyhinii is the only one that does not measure 12 millimetres in 

 diameter. 



The " explanate " forms, N. exponens, N. yranulosa, N. Pla- 

 centula, N. Spira, and the little N. Leymeriei, are sinuo-radiate 

 Assilines, certainly of no more than subvarietal value. 



Of the fiat or complanate " sinuatse " there are ten named 

 species in the Monograph : N. complanata*, N. Dufrenoyi, N. 

 Puschi, N. latispira (a dwarf), N. Carpenteri, N. distans, N 

 Gyzehensis, N. Caillaudi, N. Lyelli, and N. Carteri. The last- 

 mentioned is (according to Dr. Carter's figure and description) 

 a slightly granulated N. complanata, such as we have from Dax. 



The little N. Tchihatcheffi is perhaps a dwarf of the " sinuate" 

 group, in which D'Archiac and Haime have placed it. 



N. Pratti, N. irreyularis, and N. Murchisoni are, in all proba- 

 bility, extremely depressed forms of the same group. 



Lastly, we have seven forms belonging to the " reticulate " 

 group : namely, N. laevigata, N. scabra (granulate), N. sublaevi- 

 gata, N. intermedia (less than 12 millimetres in diameter), and 

 the still smaller forms, N. Garanensis, N. Molli, and N. Lamarcki. 



The little granulate N. Fichteli may belong to the " reticulate" 

 group, as intimated in the Monograph. 



Of the characters that appear to distinguish the several Num- 

 mulinae, none have more value than the style of growth of the 

 alar portions or lateral processes of the segments. We are, how- 

 ever, at the outset met with the difficulty, that even the existence 

 of an alar prolongation of the segment is not a specific character. 

 The " radiate " Nummulines afford instances of the variable 

 growth of these alse, and even of their becoming obsolete in in- 

 dividuals that have some segments well developed into alse. In- 

 deed the gradation from Nummulina to Assilina and to Opercu- 

 Una is, as Dr. Carter has already intimated (Journal Bombay 

 Branch Roy. Asiat. Soc. vol. v. 1857, p. 124, &c), well-marked, 

 and indicative of specific unity. The Operculina canalifera of 

 Varna, and the recent Operculina of Australia and other locali- 

 ties, take on the alar growth, converting themselves into Num- 

 mulina ; or, vice versa, we see " radiate " Nummulina lose their 

 * We have granulate specimens from Dax. 



