PROFESSOR STRUTHERS. 



dorsal, and irregular. No definite trace of it can be recognised 

 on the 7th dorsal. 



[No certain trace of this suture can be seen in this B. musculus.] 



13. NEURAL CANAL. In height the canal shows very little 

 difference along the dorsal region, from 3f inches at the first to 

 the same at the last dorsal. It is 3 J at the 8th, 9th, and 10th, 

 the highest part of the whole canal. Along the lumbar region 

 it falls from 3J to 3 ; along the caudal region from 3 at the 

 1st to If at the 5th, and to f inch at the 10th caudal. The 

 breadth diminishes backwards with slight exception, as seen in 

 Table II. At the 10th dorsal, the breadth is but half what it 

 is at the 1st (7J inches). From the 10th dorsal (3J) to the 7th 

 lumbar (3|) there is very little change. 



The floor of the canal presents the longitudinal elevation, 

 with the concavity and foramina on each side of it, noted with 

 the bodies. In the dorsal region the general concavity of the 

 side, of the Gothic arch form, is interrupted by an inward bulge 

 opposite where the lamina and pedicle meet. In the lumbar 

 region this minor convexity is higher up. At the 4th caudal 

 the canal assumes an almost square form, changing to a rounded 

 or oval form at the 7th and in the three remaining vertebrae 

 which possess a completed neural arch. 



[In B. musculus the height of the canal increases from the 1st dorsal 

 (3 inches) to the llth (4|), and then diminishes (at last dorsal, 3f ; 

 at 1st caudal, 3|). The breadth diminishes backwards along the 

 dorsal region (1st dorsal, Ty 1 ^ ; last dorsal, 3J) ; increases a very 

 little in the anterior two-thirds of the lumbar region, and again 

 diminishes backwards. Except on the first three dorsal the height 

 of the canal is greater all along than in Megaptera. The breadth is 

 about the same in both from the 3rd dorsal to the 8th lumbar, 

 behind which it is greater in B. musculus than in Megaptera.] 



ARTICULAR PROCESSES. 

 (Dorsal, Lumbar, and Caudal.) 



14. GREAT ANTERIOR ARTICULAR PROCESSES. The specially 

 developed articular surfaces of the five or six anterior dorsal 

 vertebrae are seen to be very different in Megaptera and B. 

 musculus when the two series are laid together. In Megaptera 



