112 CANADIAN FOSSILS. 
flattened specimens. The species Graptolithus (Climacograptus) bicornis 
may be considered as the type of the genus; and I conceive that most of 
those described as G. sealaris are veritable species of this genus; among 
these I would cite pl. i, figs. 5 and 6, and pl. i, figs. 14, 15, and also 
figs. 7 and 8, Barrande, Graptolites de Bohéme. In the latter figure 
the axis lies obliquely across the cell-apertures, a feature similar to that 
shown in plate A, fig. 14, of this memoir. Graptolithus teretiusculus, 
Hisinger, G. rectangularis, McCoy, and many of the figures on tab. i 
and tab. i of Geinitz’s Graptolithen, belong to this type. 
In suggesting a generic name, I have recognized the original specific 
designation of Linneus, G. scalaris. 
The form of cellules in the peculiar group of which G. ramosus may be 
considered the type, is very similar to G. bécornis, and should be separa- 
ted from Graptolithus proper for the same reason, forming a sub-generi¢ 
group, for which I suggest the name of Dicranograptus. 
CLIMACOGRAPTUS ANTENNARIUS, Hall. 
Plate XIII, figures 11-13. 
(GRAPTOLITHUS ANTENNARIUS, Hall: Geology of Canada, 1863, page 955.) 
Description.——Stipes small, simple, quadrangular, flattened, slightly 
narrowed towards the base. In their natural condition they have been 
slender sub-quadrangular tubes, celluliferous on two sides, and having a 
width when flattened, including the denticles, of thirteen hundredths of an 
inch. Axis strong, extending beyond the upper extremity of the stipe, 
and sometimes marked by a longitudinal groove : base obtusely pointed, and 
having the axis slightly extended in the middle with two setiform processes, 
one from each side, diverging at an angle of about 60° with the axis, 
and slightly curved, the two including an angle of from 120° to 125°. 
Cellules short, nearly twice as wide as long; cell-denticles nearly rec- 
tangular to the axis, and frequently inclmed; from about twenty-four 
to twenty-eight in the space of an inch. Surface smooth, and the test 
extremely thin. 
Under this species I have included individuals having the same habit 
and form, but varying in the distance of the cellules, and presenting much 
variety of aspect from the different directions in which the stipe has been 
compressed. In some examples, the margins of the stipes present rec- 
tangularly-projecting processes or spinules, which vary from being barely 
