16 ; CANADIAN FOSSILS. 
sub-linear stipes, bearmg a range of cellules on each side, often showing 
an initial pomt orradicle at the base, and an extension of the slender axis 
above and beyond the celluliferous portion. 
From these forms witha double series of cellules, we pass to the broad 
foluform stipes, which are apparently composed of four semi-elliptical 
parts conjoimed along their straight sides, and thus present four ranges of 
cellules. These forms (Phyllograptus) are, in some species, broad and 
short, while others are elongate, with sub-parallel sides, as shown in the 
accompanying figures. 
[See also plates xv and xvi. ] 
Fig. 22. 
PHYLLOGRAPTUS AUGUSTIFOLIUS. PHYLLOGRAPTUS TYPUS.: 
(See illustrations under generic descrip- a group of separated stipes as they lie upon 
tion, and plates xv and xvi.) the surface of the shale. 
From the occurrence of a large number of these leaf-like stipes, some- 
times crowded together in a small space, I have inferred that they may 
have grown as Retiograptus. (Plate xiv, fig. 9.) 
Following the forms with a double series of cellules, are those of similar 
general form, the Retiolites, which are known only as simple stipes. 
(Plate xiv, figs. 1-5.) 
In the Retiograptus we have simple elongate stipes; and in one form 
(plate xiv, fig. 9) we have the stipes united by slender basal extensions 
in a spreading frond, in a manner not unlike some of the graptolites 
proper, with the parts in bilateral arrangement. 
In the genus Rastrites of Barrande we find a departure from all of 
the preceding forms in the slender stipes with delicate ‘slender tubular 
