ME. W. H. FLOWER ON THE OSTEOLOGY OF THE SPEEM- WHALE. 33.3 



the outer margin of the articular facets. The broad flattened lateral parts of the 

 neural arch rise from directly over the upper edge of the articular facets, and converge 

 rapidly together to form the anterior surface of the broad rugged mass constituting the 

 neural spine. On the right side is a raised flat surface corresponding and fitting to 

 that described on the commencement of the arch of the atlas. The opening of the 

 neural canal, as seen in this aspect, is a transversely elongated lozenge, with the angles 

 rounded off', 8^" broad, and 6^" high. The inferior margin is very indistinctly marked 

 in the middle, — the anterior surface of the axis above the rudiment of the odontoid 

 process gradually passing into the flattened floor of the neural canal, which continues to 

 rise throughout the cervical region. 



The sides of the mass formed by the conjoined bodies slope gradually downwards 

 and inwards, converging towards the middle line, where they meet in a slightly elevated, 

 rounded, longitudinal keel, in which all trace of the original separation of these vertebrae 

 and even of the first dorsal is entirely lost. 



As in the Toothed Whales generally, the transverse process of the axis consists of a 

 single, broad, imperforate plate, springing from the greater part of the side of the body 

 of the bone and the lower part of the neural arch, representing, in situation at least, 

 the upper and lower processes found in the succeeding vertebrae (and in the axis of the 

 Whalebone-Whales), coalesced and with the intermediate space filled up. In relation 

 to the large size of the body of tlie bone, these processes may be considered short : 

 the condition of the ends, in the Tasmanian specimen, shows that they have not quite 

 attained their complete ossification ; but they are only very slightly longer proportionally 

 in the completely adult Caithness Whale. They are much compressed from before back- 

 wards, and obliquely truncated externally, the nearly straight end looking upwards and 

 outwards. In the older specimen more advanced ossification of this apophysis has caused 

 the end to approach nearer to a vertical line. 



In most Cetacea the inferior transverse process of the cervical vertebrae {parapophysis, 

 Owen), arising from the side of the body, increases in development from the third to 

 the sixth, and suddenly becomes obsolete, or nearly so, in the seventh, where the 

 articular facet for the head of the first rib appears as it were in its place, situated, 

 however, not precisely at the same spot on the side of the vertebrae, but rather above 

 and posterior to it. In all known genera of Delphinoids the inferior process of the 

 sixth vertebra attains a considerable development, most strikingly so in those in which 

 the vertebra are free, as Beluga and, especially, Hatamsta. In Hyperoodon it is very 

 conspicuous, although the third, fourth, and fifth show no rudiment of the process. 

 In that genus also, at least in one example (Mus. Roy. Coll. Surg. No. 2480 a), con- 

 trary to the general rule, a tolerably long inferior process is developed from the body of 

 the seventh vertebra, but on the right side only. In the Tasmanian Sperm- Whale there 

 is no trace of an inferior transverse process on the smooth sides of the bodies of any of 

 the cervical vertebrae as far as that which appears to be tlie sixth, inclusive. The lower 



VOL. VI. PART VI. 3 A 



