Nomenclature of the Foraminifera. 475 



g. Var. D. glandulosa. Vicomte d'Archiac has figured and 

 described a fossil Microzoon (Prattia glandulosa, Mem. Soc. Geol. 

 France, 1850, iii. p. 407, pi. 8. f. 20; Bronn, Leth. Geognost. 

 3rd edit. i. p. 28, pi. 35 3 . f. 28) from the Eocene beds of Biar- 

 ritz, which appears to us to be a Dactylopora, bearing the same 

 relation to D. reticulata as D. marginoporella does to D. annulus, 

 and D. digitata to D. eruca. We can easily suppose rings of 

 loosely set chambers piled one on another, and, instead of form- 

 ing the neat, cylindrical, cane-like form of D. reticulata, pre- 

 senting a subcylindrical hollow body, externally roughened by 

 numerous vesicular projections, and occasionally intersected by 

 faint annular rings indicative, as it were, of periodicity of 

 growth. It is thus that we interpret the specimen alluded 

 to ; and we propose to recognize it as the variety D. glan- 

 dulosa. 



h. Var. D. polystoma. Another variety, from Grignon, illus- 

 trative of the transitional characters of Dactylopora, has three or 

 more apertures to each cell (hence its proposed name D. poly- 

 stoma). Besides the single internal mouth, opening into the 

 hollow cylinder of this compound shell, there are externally at 

 least two apertures, strongly labiate, one opening near the 

 base, and the other at the top of the cell. In the first or earliest 

 ring of cells, only the upper row of openings is present. The 

 fine specimen from which our observations were made is curved, 

 and the convex side shows at several places the interseptal pas- 

 sages ; where these are not visible, the rows of upper and lower 

 apertures of contiguous cell-rings form distinct annular bands, 

 between which the outer wall of each cell is boldly defined, and 

 often broken through ; so that three kinds of superficial perfo- 

 rations here tend to perplex the observer. 



i. D.Bambusa (type). The stages through which Dactylopora 

 passes in attaining its most compound condition are very curious, 

 and not, at first, readily followed. We may describe them 

 thus : 



In each of the original cells the exterior apertures become tu- 

 bular, and arise from the sides, not from the outer part of the 

 cell. Next we see the cells giving off three or more stolons 

 (from the side and rather towards the neck), which pass through 

 the thick shell, and open as simple round apertures on the 

 surface, which is also characterized by annular rows of much 

 larger passages, the latter being the junctural interspaces. This 

 form we call D. Bambusa. 



j. Var. D. cylindracea. Moreover, we find in some specimens 

 that each of the original cells has produced from its outer 

 surface, or fundus, a new oval or subglobular chamber, larger 

 than itself, the neck of the new chamber being closely adapted 



