220 REPORT ON THE STATE CABINET. 



I am able to corroborate, to some extent, the observations of M. Bar- 

 RANDE in regard to the apparent double character of this axis. In some 

 extremely compressed specimens, it is marked by a longitudinal groove 

 or line of division ;* while in others, a double impression has been left 

 by the removal of the substance. 



In some specimens, particularly the younger ones, the solid axis has 

 been seen extending beyond the base of the stipe, as a duplicate process, 

 exhibitmg a character as of a double radicle. In several species there is 

 on each side a lateral process of similar character, extending rectangu- 

 larly or obliquely downward from the base of the lower cellules, and 

 usually having a greater length than the initial point itself. This feature 

 is shown in the germs and young Graptolites on Plate i, and in figures of 

 Graptolithus {Climacograftus) bicornis^ Plate ii. The same feature is shown 

 in a more extreme degree in G. (C.) atemianus of the Quebec group. t In 

 some solid specimens of one species, where the tube has been filled with 

 calcareous mud, I am able to detect only a single round point in the centre 

 of a transverse section ; and a longitudinal section of the same species 

 presents a slender filiform axis. It may be, however, that the parts are 

 so minute and so closely united, as to render them undistinguishable. 



In another species, with two rows of cellules, and in which the latter 

 are of very different form from the preceding, the solid axis is a thin 

 flat apparently double plate, extending across the entire transverse 

 diameter of the tube, which is more than two-thirds as great as its 

 longer diameter. The place of the axis is marked by a longitudinal groove 

 on each side, not in a direct line, but slightly undulating to correspond 

 with the cellules (Plate ii, fig. 10). M. Barrande conceives that the 

 joining of the two plates of this axis may leave a very flat intermediate 

 tube; and in our specimen, there is apparently an extremely narrow 

 space between the two. He farther supposes that each of these plates, 

 composing the double axis, is separable, by decomposition, into two 

 laminae, as illusti'ated in Plate iii, fig. 3, of the work already cited. 



The entire appearance of the species (Plate ii, fig. 10), is that of two 

 monoprionidian stipes joined together at the back, the line of junction 

 being indicated by the groove. 



In one species of Retiolites, there is a strong eccentric or sub-exterior 

 axis, which is nearly direct; and in the same individual there is another 



* The aspect presented by the axis, when marked by a longitudinal groove, is precisely that 

 which a hollovr cylindrical body would have if extremely compressed. 



I Graptolites of the Quebec Group, Decade ii. Geol. Survey of Canada, PI. 13, figs. 12 and 13. 



