GRAPTOLITES. 83 
- their width; and in the narrower stipes, the length of the cellule is 
about five times the width. There are from twenty-four to thirty-two 
cellules in the space of an inch: (the specimen having thirty-two in 
an inch is a young individual, in which the cellules are more crowded, 
and not fully developed.) The apex of the denticle is vertically above 
the base of the fourth or fifth cellule in advance, varying in the narrower 
stipes to the third cellule in advance. 
This species differs from all the others described, except G@. bifidus ; 
and this it very much resembles in the young individuals. There is an 
absence of pustules at the base of the cell-partitions, with a greater thick- 
ening of these partitions, and the denticles are usually more mucronate. 
If uniformity im the divergence of the stipes can be relied upon, this char- 
acter will aid in distinguishing the species ; but this feature may vary from 
accident, as In one specimen figured, which appears to have been broken in 
one of the stipes. This species is remarkable for the great development 
in the width of the stipes, which, in their extremely compressed condition, 
have the appearance of feathers mbedded in the shale. 
The specimens from which these figures have been drawn, present the 
fossil in a very unsatisfactory condition; and farther collections may show 
the necessity of separating some of the narrower forms under another 
specific designation. 
EXPLANATIONS OF Figures oF GRAPTOLITHUS PENNATULUS, Hall. 
Puate III. 
1, A young specimen with the minute radicle, the stipes diverging almost horizon- 
tally, or rectangularly to the radicle. 
2, A young specimen with one stipe entire, and a part of the other, less divergent 
than fig. 1. 
3. A single imperfect stipe of a young or half-grown individual, which is narrower 
than usual. 
4. A larger stipe, which is entire from the base to the apex. 
5. A large or full-grown single stipe, which is nearly entire. 
6. An enlargement to three diameters from fig. 4, showing the form and proportion 
of the cellules, and cell-denticles. 
7. An enlargement to the same degree as the preceding, from fig. 5. 
8. A young specimen where the stipes are twisted near the base, giving an appearance 
as if the serrations were on the outer or lower side in relation to the direction 
of the radicle. 
PLate V. 
9. A single stipe of this species? The specimen is a large stipe, somewhat obscurely 
preserved upon the surface of a slab of slate, with G. extensus, G. bryun- 
oides, and Phyllograptus ilicifolius. It is from the same locality with 
G. bifidus at Point Lévis. In the form of the stipe, and its gradual diminu- 
tion towards the distal extremity, as well as in the absence of visible pus- 
tules at the base of the cellules, it has the habit of G. pennatulus. Being 
the only individual observed from this locality, and the resemblance to 
G. bifidus being very close, I haye referred it with much hesitation to 
G. pennatulus. 
