1865.J GRAPTOLITES OF THE QUEBEC GROUP. 47 



from which the buds, with their calycles forming the cellules, take 

 their origin, and are thrown off at regular intervals. 



All the specimens which I have examined confirm this view ; 

 and in some of the species where the extremities are apparently 

 entire, we observe the incipient development of the young cell from 

 the common body. In those specimens filled or partly filled with 

 the substance of the surrounding rock, this canal is easily dis- 

 tinguished; while in compressed specimens there is always a 

 flattened space between the bases of the cell-partitions and the 

 solid axis. 



In those graptolites with two ranges of cellules, we have ap- 

 parently a duplication of those with the single series, the two 

 solid axes being joined together, leaving a common canal or body 

 on each side at the base of each series of cellules. If however the 

 common body were thus divided, it would be by the solid axis, 

 becoming a flattened plate. This appears to be true of some species, 

 while in others there is only a simple filiform axis visible. In 

 this case, of course, there is not an entire division in the common 

 canal after the manner of the other species. This will app ar 

 further on, under the illustrations of the structure of these bodies. 



3. The Calycles or Cellules ; their form and mode of develop- 

 ment. — Since a large proportion of the specimens of graptolites 

 which come under our observation for the purposes of study or 

 otherwise, are fragmentary, it becomes of much importance to 

 know the general characters of form and mode of development of 

 the cellules. 



In the preceding section it has been shown that the cellules, or 

 the inhabitants of these cellules, are not independent, but all have 

 their origin in a common body, which fills the longitudinal canal, 

 and that they remain in constant connection with the same throu°h- 

 out their existence. 



The calycle or cellule is formed by budding from one side of the 

 common body, not unlike many of the Sertularians, except that 

 the cellules are generally close together at their origin. They 

 are usually more or less oblique to the direction of the axis, as is 

 clearly indicated by the cell-partitions ; and the degree of obliq- 

 uity often indicates specific distinction. The cellules are for the 

 most part contiguous at their origin, and they sometimes remain 

 in contact throughout their entire length ; but in the greater 

 number of species there is a small portion of each one free on one 

 side towards the aperture. This character is shown in numerous 

 examples. 



