OF BAL^NOPTERA MUSCULUS. 



217 



in the cervical region liave already been sufficiently mentioned. The great lateral masses 

 of the axis incline strongly backward, particularly towards the upper surface. The pro- 

 cesses of the 3d and 4th cervicals have the same inclination to a lesser degree ; those of 

 the 5th are about straight, and those of the 6th and 7th incUne forward so that the ex- 

 tremities of the transverse processes from the 2d to the 7th cervical very nearly touch one 

 another. All these pro- 

 cesses, except the 7th, 

 are exceedingly thin, and 

 that of the 3d dorsal is 

 the first in which the 

 thickness is greater than 

 the height ; all the sub- 

 sequent ones are thin and Fi^. 7 _ ^t^ Cervical Vertebra. 



compressed from above 



downward. The thin superior edges of the cervical transverse processes present each a 

 small, rough elevation {B in woodcuts,) at some distance from the body, which are serially 

 homologous, with a similar projection from the axis. In the 2d and 3d cervicals the trans- 

 verse processes spring almost entirely from the pedicles, but in the following vertebrae they 

 arise more and more from the bodies. In the first six dorsals the origin is very extensive, 

 for though they really arise from the bodies, the line forming the posterior superior border 

 runs up into the arch. In the 7th dorsal this line disappears and they continue to arise 

 successivel}^ lower. In the 5th caudal they arise from a point a little below the centre of 

 the body ; in sorne of the subsequent ones perhaps a little higher, though not above the 

 centre. 



With regard to shape and direction the first five dorsals incline forward like the latter cer- 

 vical vertebra ; a few are then about straight, after which a slight backward tendency 



appears. In the 5th dorsal 

 an angle appears in the an- 

 terior border and the part 

 external to this is directed 

 backward ; this persists 

 throughout the dorsals, and 

 reappears from the 9th lum- 

 bar to the 4th caudal. The 

 general backward inclination 

 ends with the anterior lum- 

 bars, and after a few vertebrte a forward one is substituted which continues to the end. 

 In the 8th caudal the base becomes long and perforated, and persists so till the 14th, with 

 which the transverse process ceases to exist. The greatest distance between the extremi- 

 ties of the transverse processes of a vertebra occurs in the 2d lumbar, with Mr. Murie in 

 the 4th. The ends of these processes are hollowed in the dorsal region for the tubercles 

 of the ribs. The depression in the first two is at the end, but subsequent ones are hol- 

 lowed below. The fossa is very deep in the 4th, 5th, and 6th, bounded anteriorly by an 

 oblique ridge which ends internally in a sharp point. The posterior fossae are less and less 



Fig. 8. — 6tb Dorsal Vertebra. 



MEMOIRS BOST. SOC. NAT. HIST. VOL. II. 



55 



