MR. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 347 



middle by these grooves on each side below, and by the one connecting the two fora- 

 mina (here much reduced in diameter) on the upper surface, that at first sight it looks 

 like two vertebrse which have coalesced, as not unfrequently occurs in this region among 

 true Whales. The last vertebra is a rough, broad, oval nodule of bone, truncated in 

 front, obtusely pointed behind, flattened from above downwards. Traces of the vascular 

 grooves are to be detected on its sides. The contiguous surfaces of this and the penul- 

 timate are both concave ; but the irregularities of their prominent edges correspond 

 exactly, and they have evidently been in close apposition. 



The last twelve vertebrae of the tail of another Cachalot, sent to the Museum by 

 Mr. Crowther in 1866, resemble those of the skeleton in their general characters, 

 and evidently correspond vertebra for vertebra, but with considerable individual de- 

 viations. They are, in the first place, all rather shorter in proportion to their breadth. 

 The entu-e length of the twelve placed in apposition is 38", while the twelve cor- 

 responding vertebrse of the skeleton measure 42", the breadth of the former slightly 

 exceeding that of the latter. The neural arch is not completely closed in by bone 

 even in the fii-st of the series. The penultimate is much shorter than that of the 

 specimen described above. The terminal vertebra is altogether smaller, and does not 

 present the broad, depressed character of the other, but is a simple rough subconical 

 nodule. The first of the set had a perfect chevron bone attached to its hinder edge, 

 5|-" in greatest depth, and 4" in length. The second had another, consisting of two 

 distinct oval plates 21" deep by 2^" long. There were no further traces of hsema- 

 pophyses, which, from the state of the specimen, must have been preserved if they had 

 ever existed. 



The Tasmanian, Sydney *, Caithness, and Yorkshire Cachalots resemble each other in 

 possessing a distinct atlas, followed by six ankylosed cervical, and ten dorsal vertebrse 

 bearing well-developed ribs. They agree, moreover, in possessing eight true lumbar 

 vertebrae. The Sydney specimen, however, according to the published description, wants 

 the vertebra intermediate between the dorsal and the lumbar series, found in the other 

 three, and hence has one vertebra less in front of the first chevi-on bone. Of remain- 

 ing or caudal vertebrce, the Tasmanian and Sydney specimens have twenty-four, the 

 Yorkshire specimen (presuming it to be complete) twenty-three, while in the Caith- 

 ness one the number cannot be stated with certainty. The Yorkshire and Sydney 

 Cachalots, therefore, agree in the entire number of vertebrse being forty-nine, while 

 the Tasmanian skeleton possesses fifty. These dififerences are so trifling that tliey 

 may be the result of accident or individual peculiarity; they certainly by them- 

 selves afi'ord no assistance in discriminating between a northern and southern species of 

 the genus. 



Nor do we find, on reverting to the special characters of the vertebrae, any m )ie 



* Wall, oj^>. dl. 



