Dr. H. A. Nicholson on the Genus Climacograpsus. 373 
England. These specimens, as I m elsewhere mentioned 
Quart. Journ. Geol. Soc. vol. xxiv. p. 529), very readily split 
up, entirely or partially, into their pondo halves—thus 
exhibiting the structure of the frond in an exceedingly beau- 
Fig. 1 
oN 
a. Specimen of Climacograpsus teretiusculus, His., showing the notch-like 
cell-apertures = the distal and proximal extensions of the axis; twice 
the natural size: from the Upper rrr Shales of d Linn, 
near Moffat. ‘pede en of the same in a sc ee a w, showing 
the mouths of the mare i twice the natural siz : Upper Llandeilo, 
x Cpu near joue c. Specimen of the bd in relief, show- 
ing ure ich enlar: 
stones Skel ETE Il Beck, puc yc d. beso of a scalariform 
8 same, much e — € , near M 
e. Ario or fea enlm greatly — Skiddave Slates. f-A specimen 
in relief, ‘but split in half till cl n the base, showing the median 
septum 'and the solid axis ramet 6 jue its centre ; twice the euis, 
size: Mudstones of the Coniston series. g. Transverse section of a 
ne of C. teretiusculus, —— in the round, showing the me- 
dian septum and the solid axis 
