388 



ADDITIONS AND COEKBCTIONS. 



straight lower edge ; it is thickest ia the middle. The upper surface 

 is shelving on the sides, with an angular central prominence. The 

 central aperture is very large, nearly circular, and dilated above 

 iato an oblong transverse aperture, which is rather wider than the 

 widest part of the central circle. The front articulating surface is 

 horseshoe-shaped, continued to the upper outer angle, and obliquely 

 shelving off on the upper edge to the base of the oblong part of the 

 aperture. The articulating surface of the hinder side is similar; 

 but the articulating surface is shorter at the sides, and transversely 

 truncated iu a Hue with the middle of the upper, oblong, transverse 

 opening (figs. 94, 95). 



Meganeuron, Gray, P. Z. S. 1866, 440. 



Inhab. Austraha. 



Kg. 95. 



Pig. 94. 



Fig. 94. Front of atlas of Meganeuron Krejftii. 

 95. Hinder side of ditto (reduced). 



" In a letter which I lately received from Mr. Gerard Krefft, the 

 intelligent Secretary and Curator of the Australian Museum, he sent 

 me some photographs (taken like those he formerly sent by Mr. Henry 

 Barnes) of a separate atlas vertebra and of the second and other 

 cervical vertebrse united into one mass of a species of whale, which 

 are contained in the museum under his charge. The two bones, 

 though not united, fit one another so exactly that Mr. Krefft has no 

 doubt of their having belonged to the same animal ; and the photo- 

 graphs sent justify this conclusion. However, should there be any 

 mistake in this matter, it wiU not in the least invalidate the con- 

 clusion that I have come to, from the examination of these photo- 

 graphs, that they indicate the existence of a second species of Sperm 

 'Whale in the Australian seas, very distinctly characterized by the 

 subcircular form of the atlas vertebra and of the neural canal in it. 



" The mass formed by the second and other cervical vertebrae is 

 somewhat similar to these bones in the skeleton of the Australian 



