part 3] CHAROPHTTA OF THE LOWER HEADOjS^ BEDS. 191 



exterior about 450 /x. The apparent thickness of the cell-wall is 

 evidently in part due to encrustation. The branchlets are six in 

 number, and the internal diameter is about 250 jj. 



The small number of the branchlets and the apparently ecorti- 

 cate stem suggest the possibility that it belongs to one of the 

 Nitellece, perhaps Tolypella lieadonensis, the fruits of which come 

 from the same bed. 



Some remains, collected by Mr. Reid from the Basement (Seed)- 

 Bed, had not been examined during his lifetime. This gathering- 

 has proved particularly valuable, as in addition to the entire 

 oospores present in situ, referred to under species 1, 3, & G, it 

 includes a fair quantity of the vegetative parts, among which there 

 are several more or less complete stem-nodes with small portions of 

 the internodes and branchlets attached. This vegetative material 

 is unfortunately very much encrusted and extremely friable, so that 

 it is almost impossible to make out some of the details of structure. 

 The portions of detached stem, some of which are Avell preserved, 

 all apparently belong to one of two types. Of Type 1 the inter- 

 nodal cell ranges from about 375 to 500 fj. in diameter, and has a 

 haplostichous cortex formed of ten contiguous or almost contiguous 

 rows of large cells measuring about 100 to 125 /j in diameter. The 

 cortical cells are frequently nodulose, and on some of them there 

 are apparently clusters of three or four spine-cells. The stem 

 therefore resembles among living species the uncommon but 

 widely distributed Clicira canescens. An imperfect node showing 

 corticate branchlets probably belongs to the same species ; but 

 there is no portion of the stem-internode attached. 



Type 2 has the internodal cell of about the same diameter, with 

 a haplostichous cortex formed of about ten distinctly non-contiguous 

 rows of small cells of less than half the diameter of those of Type 1. 

 Most of the stem-nodes appear to belong to this type, and the 

 branchlets apparently are uniformly ecorticate and about ten in 

 number. There are traces of fairly large stipulodes on some of 

 the nodes, but the encrustation prevents them from being clearly 

 seen. In one instance there are sections of a large number of 

 outstanding cells at the base of the branchlets. In others there 

 appears to be onl}^ one stipulode to each branchlet. The stem- 

 cortex of this type resembles among living species that of the rare 

 Western European and North African Ghara imjyerfecta^ but that 

 species has rudimentary stipulodes. 



EXPLANATION OF PLATES lY-VI. 



[All the figures are mag-nified 20 diameters, except figs. 9 & 21 in PI. VL] 



Plate IV. 



Fig. 1. Chara WngJitii. (See p. 183.) 



2. C. WrigJitii, var. minor no v. 



3. C. Wrightii, var. rJiytidocarpa nov. 

 Figs. 4-6. Chara caelata, sp. nov. (See p. 184.) 



Q. J. G. S. No. 307. Q 



