part 3] CHAllOPHTTA OF THE LOWER IIEADOX BEDS 185 



var. haccata, which maj be a distinct species, they are broader 

 (quite lialf the breadth of the spiral cell) and almost contiguous. 

 We found one fruit in the Mammal- Bed closely reseml)ling that of 

 C. ccelafa, but having holes at regular interv^als in place of tubercles 

 (PL VI, fig. 9). 



Obtained from the Limestone-Band, and one specimen of C, 

 ccelata var. haccata from the Basement (Seed)-Bed. 



3. Chara TASiroEMTS, sp. nov. (PI. lY, figs. 12-15.) 



Oogonium obovoideum deorsum ad basem insignem pentagonum 

 plerumque fastigatum, magnitudine variata, long. c. 750-950 />«, 

 crass, c. 475-725 a ; cellulae spirales lat. c. 75-100 /j, crass, c. 50-00//^ 

 apice paulo dilato, cum ordine tuberculorum eminentium trunca- 

 torum, convolutiones decem-duodecim exhibentes ; foi'amen basilare 

 plerumque latum infundibuliforme. [Oospora obovoidea, long, 

 c. 650-725^1, crass, c. 450-500//, liras eminentes c. novem exhibens : 

 cohors basilaris diametro c. 125^.] 



A well-mai"ked fruit verv variable in size, usuall}" pale brown. 

 Evidently allied to C. tiihercidata Lyell, from the Bembridge 

 Beds, but differing in its smaller size, in being more or less obovoid, 

 rather than ellipsoid, and in having usually a more prominent vase- 

 like base, which latter feature does not come out well in our figures. 

 The tubercles of the other tuberculate-fruited species are either 

 rounded or conical, whereas in C. tnherculata and C. vasiformis, 

 when fully developed, they are abruptly truncated, the apex being 

 fiat. The probable explanation of this is that the extent of their 

 development was limited by the cell wall. In a very small pro- 

 portion of the fruits the tubercles are absent (see fig. 14). In 

 some there are smaller irregular intermediate tubercles forming a 

 serrated ridge along the centre of each spiral cell. We were in 

 doubt as to the origin of the tubercles : that is, whether they were 

 possibly merely a calcareous encrustation, or were organic. Our 

 friend, Mr. D. J. Scourfield, a skilled microscopist and biologist, 

 kindly made a careful examination of them, and reported as 

 follows:— 



' The tubercles are very peculiar, but I have come to the conclusion that 

 they are actual prorluctions of the plant. If a piece of a spiral be examined, 

 it will be seen that, despite much irreg'ularity of growth along- the whole 

 course of the spiral, the more or less flat-topped projections (that is, the 

 tubercles properly so called) are spaced at fairly constant interyals. The 

 amount of these growths varies from nothing- on some specimens to an almost 

 continuous band on others. I suppose that this depends on the stage of 

 develoiDment of the fruit. If a piece of one of the spirals be treated with 

 weak acid the carbonate of lime will be seen to ba gradually dissolved away, 

 leaving- an exact copy in some organic substance (? cellulose) with a rather 

 wrinkled surface. A number of very minute crystals (? substance) are 

 embedded in this, and also usually a number of somewhat rounded grains, 

 probably sand-grains, as they do not dissolve in fairly strong nitric acid.' 



From the Limestone-Band a few fruits were obtained, of which 

 the apex was f)i'olonged into a point. (See PI. IV, fig. 15.) 



