92 CANADIAN FOSSILS. 
resemblance to G. arcuatus, except that it is less curved, and the form of 
the cellules is distinctive. From the other bibrachiate forms, it is very 
readily distinguished on comparing the form of the cellules. 
I had heretofore regarded this species as possessing a disc, like G. 
crucifer and others ; but on examination of all the specimens which can 
be satisfactorily identified with it, not one has showna disc. The discs with 
four stipes, which are broken off so close that no serratures are visible, 
cannot be satisfactorily identified with this or any other species, and are 
therefore left in doubt at this time. They may be regarded as belonging 
to G. crucifer, or to the young of G. Headi. 
EXPLANATIONS OF FIGURES OF GRAPTOLITHUS QUADRIBRACHIATUS, Hall. 
PLATE V. 
1. A large specimen with stipes vertically compressed. 
A young specimen in which one of the stipes appears to be subdivided. 
8. An individual with stipes a little curved, the back of the stipe visible, and showing 
no serratures. 
4. A frond with one of the stipes broken off; one showing the cellules and distinct 
striz parallel to the cell-partitions, while the other two are turned so as to 
obscure the cellules. 
5. An enlargement from fig. 1: the stipe has been vertically compressed, causing 
the cellules to show a less angle with the stipe than in the normal condition. 
PuaTeE VI. 
5. A frond preserving one stipe partially entire, and others broken off: the funicle 
and radicle-point are well preserved. 
6. An enlargement from the specimen fig. 5, showing the form and proportion of 
cellules in their more perfect preservation, with the striz parallel to the cell- 
margins well preserved. 
Formation and Locality.—Shales of the Quebec group; Point Lévis. 
16. GRAPTOLITHUS CRUCIFER, Hall. 
Plate V, figure 10. 
(G. crucirer: Geological Survey of Canada, Report for 1857, page 125.) 
Description.—Frond composed of four simple, strong stipes, united at 
their base by a small thickened disc. Stipes strong at the base ; the two 
pairs connected by a short funicle, which is without a visible radicle. 
