Dr. J. E. Gray on a new Sperm Whale. 287 



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

 cervical vertebrae 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 will not in the least invalidate the conclusion 

 that I have come to, from the examination of these photographs, 

 that they indicate the existence of a second species of Sperm Whale 

 in the Australian Seas, very distinctly characterized by the subcir- 

 cular 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 

 Catodon lately received by the Royal College of Surgeons, which I 

 hope will shortly be described by Mr. Flower, the energetic Curator 

 of their Museum, who, in his late paper on the Balcenidee, has shown 

 how well he can describe and determine the species of Whales. 



The genus Catodon should be divided into two subgenera, accord- 

 ing to the form of the atlas, thus : — 



I. The atlas oblong, transverse, nearly twice as broad as high ; the 



central canal subtrigonal, narrow below. Catodon. 



1. Catodon macrocephalus of the Northern Ocean. A ske- 

 leton from Scotland, in the British Museum. 



2. Catodon australis, Macleay, of the Southern Ocean. A 

 skeleton in the Museum of the Royal College of Surgeons, from 

 Hobart Town. 



II. The atlas subcircular, rather broader than high ; the central 



canal circular in the middle of the body, widened above. Me- 

 ganeuron. 



Catodon (Meganeuron) Krefftii, sp. nov. 



The atlas vertebra oblong transverse, about one-third wider than 

 high ; the lateral processes only a little produced beyond the articular 

 surface, with an arched edge ; the lower edge arched ; the neural 

 arch low, broad, with a slight central prominence on the upper sur- 

 face ; the canal for the spinal marrow very large, circular, rather 

 contracted on the sides above, and then dilated, becoming oblong and 

 transverse. 



The atlas is thin, high, being only about one-fourth wider than 

 it is high. The lower and lateral margins are arched, the lower 

 edge being the most so. The neural arch is low, transverse, with a 

 nearly straight lower edge. It is thickest in the middle. The 

 upper surface is shelving on the sides, with an angular central pro- 

 minence. 



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

 above into 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 



