122 ALLEN: NEW ENGLAND WHALEBONE WHALES. 



The cervical vertebrae are, in the adult, more or less completely united into a solid mass. 

 The centra are usually well ankylosed, while the neural spines and the transverse processes are 

 variously united. Thus in the Provincetown 1864 specimen, as described by Dr. J. A. Allen, 

 the spinous processes of the first to fifth cervicals have entirely fused, but the tips of the two 

 remaining are free. Of the transverse processes, those of the atlas are both free, and of the 

 remaining six, that of the second is free on the left side, but on the right side is fused with the 

 transverse process of the third, and all the rest on this side are fused together at their outer ends. 

 On the left-hand side, the third and fourth are fused, at their tips, and the fifth, sixth, and 

 seventh in a second group. This specimen is remarkable for the relatively slight degree of 

 fusion between the atlas and axis. 



Sundry measurements of vertebrae are given by Andrews (1908) and J. A. Allen (1908) 

 for American specimens. The neural spines increase in height at the shoulder region and 

 maintain their length well on to the lumbar vertebrae, whence they decline rapidly, at the same 

 time becoming strongly slanted backward. In the Provincetown 1864 whale the 41st is the last 

 vertebra to have this process and the anterior articular processes well developed, and the 45th 

 is the last to have a neural canal. The transverse processes of the lumbars and caudals differ 

 greatly from those of the Fin Whales. In these the processes are broad, thin, and flattened, 

 arising from nearly the whole length of the centrum, regularly expanding distally, and finally ter- 

 minating in an almost knifelike edge. In Eubalaena on the contrary, they arise from a much 

 smaller portion of the centrum, are oval or elliptical in section, and at the end expand slightly, 

 while instead of coming to a thin edge, they terminate with a truncate elliptical face. These 

 processes are rather long at first but on the anterior caudal vertebrae shorten rapidly and 

 become a mere ridge on the 40th vertebra and practically disappear with the 41st or 42d. The 

 vertical perforation of the transverse process first appears on the 38th (or 39th) vertebra and 

 disappears with the 45th, the last also to have a neural canal. The centra of the 38th to 41st 

 vertebrae or thereabouts are markedly larger than those preceding them, giving greater bulk 

 to the tail, while the 45th is much smaller, and those succeeding dwindle quickly in size, becom- 

 ing mere rounded ossicles. 



Some discrepancy appears in the recorded numbers of the chevron bones. There 

 are only nine in the Provincetown 1864 skeleton as mounted, but probably the series is 

 incomplete, as the posteriormost are small and easily lost. Andrews (1908) who carefully 

 dissected these bones from two Long Island specimens found twelve in one, and but nine in 

 the other and younger animal. The fifth was found to be the largest, 11.5 inches long with a 

 keel 8 inches long. 



The number of ribs is fourteen on each side. The first pair is sometimes double- 

 headed, in which case the extra head articulates with the last cervical and is really a cervical 

 rib that has become fused with the first true rib. It was on this individual peculiarity that Gray 



