22 THE VOYAGE OF H.M.S. CHALLENGER. 



epiphysial plates not in position, 88^ inches. If 16 inches be allowed for the thickness 



of these plates, and another 16 inches for the thickness of the intervertebral discs, the 



total length of the spine would have been in the fresh state 120^ inches — say 10 feet. 



The length of the skull proper was 25 inches, but as the lower jaw projected an inch 



beyond the upper, the entire skull was 2 feet 2 inches in length. The length of the 



skuU being added to that of the spine makes the length of the axial skeleton 12 feet 



2 inches, which is considerably below the length of 1 4 feet, stated by Mr Bonner, the 



captor, to have been that of the animal. Even if we suppose that, in the macerated 



condition, one or even two of the terminal caudal vertebrae were absent, and make ample 



allowance also for the thickness of the integument at the tail and beak, one cannot see 



that the animal could have been so long as stated by Mr Bonner. The vertebral 



formula was — 



C;, De, L,o, Cdis = 44 . 



It is possible that one or even two of the terminal caudal vertebrae may not have 

 been ossified, as not merely were the plate-like epiphyses not ankylosed to the vertebral 

 bodies generally, but the bones in their general aspect had all the characters of im- 

 maturity. In Dr von Haast's specimen already referred to, the A^ertebral formula was 

 C7, Dio, Lio, Cdi9 = 46. In Mesojylodon sowerhyi the formula is also 46, made up as 

 follows : — C7, Dio, Lio, Cdi9, or, according to Malm,^ Cj, Dio, L9, Cdao- In Mesoplodon 

 grayi it is, as Professor Flower has shown,^ 48 — viz., Cj, Djo, Ln, Cdjo ; and in Meso- 

 plodon australis, 47 — viz., C7, Dg, Ln, Cdjo, though in l^oth it is probable that one minute 

 terminal vertebra is wanting. 



The cervical vertehrce had in their total length an antero-posterior diameter of 

 3^ inches. The atlas, axis, and third vertebra were united into a single bone. The 

 fusion between the bodies and spines of the atlas and axis was very complete, but the 

 pedicles and transverse processes were distinct. The body of the third was ankylosed to 

 the second vertebra, but it was differentiated by a deep furrow at the place of fusion. 

 The transverse processes, pedicles, and laminae were quite distinct, but the laminae were 

 not united mesially, and there was, consequently, no spine. The breadth of the atlas was 

 6 inches, its vertical diameter was 5^: inches. The remaining cervical vertebrae were separate 

 bones, with loose epiphysial plates. Their bodies were thin plates of bones, and each 

 possessed an inferior mesial tubercle. Their neural arches were incomplete mesially, except 

 in the seventh, where the laminae were united, and a spine an inch long was produced. 

 The transverse processes not only in these posterior cervical vertebrae, but in the second 

 and third also, were divided into a superior, projecting from the neural arch, and an inferior, 

 from the side of the body, but these processes were not joined externally to form a " verte- 



' Hvaldjur i Sveriges Museer ar 1869 in Konig. Svenska Veteuskaps, Akad. Haudlingar, Baud 9, No. 2, Stock- 

 holm, 1871. 



" On the Genus Mesoplodon, Trans. Zool. Soc. vol. x. p. 428, 1878. 



