a Mandibular Ramus q/" Anthracosaurus Russelli. 77 



tached was also described in the same paper with the last- 

 named specimen. And now we have to record from the same 

 locality a fragmentary specimen of the middle portions of a 

 pair of mandibular rami displaying several teeth. These 

 fragments lie one over the other, and are much confused and 

 mixed up with some other bones that are adherent by pressure 

 to the general mass. The surfaces of the teeth, however, are 

 in a very good state : some exhibit grooves, others ridges. In 

 one of the teeth the grooves are very delicate, and are jire- 

 cisely like those in Mr. Ward's specimen. 



Besides the above evidence of the occurrence oi Arithraco- 

 saurus in the Newcastle coal-field, detached teeth are likewise 

 found at Newsham, agreeing in every particular, externally 

 and internally, with the type specimens. They are rare, how- 

 ever, in comparison with those of Loxomma^ which is un- 

 doubtedly the much commoner fossil of the two. 



Loxomma AUmanni, Huxley. 



Since our paper appeared in the ' Annals ' (May 1870) on 

 the occurrence at Newsham of an imperfect cranium oi Lox- 

 omma AUmanni, Mr. Atthey has obtained from the same loca- 

 lity another and complete cranium of this fine LabyrintliGdont. 

 This second example was procured about the middle of last 

 June, and is one of the finest and most perfect specimens that 

 have yet been found. Indeed, so far as we know, there are 

 but two others that can at all be compared with it ; and these 

 are the beautiful skulls alluded to in the above paper as being 

 in the possession of Mr. James Thomson, of Glasgow. 



Our second specimen is 14 inches long and nearly 7f inches 

 wide across the occipital region, where the skull is widest. 

 We estimated the length of the first obtained specimen, which 

 wants the muzzle, as 12 inches ; but, as it is 9 inches wide, 

 this estimate is probably considerably less than it ought to be. 

 Since we have seen that the one which is only 7f inches wide 

 is 14 inches long, we should certainly expect that the speci- 

 men measuring 9 inches across would be proportionately 

 longer. The latter could scarcely have been less, when per- 

 fect, than 15 or 16 inches in length. 



The specimen recently obtained has been entirely removed 

 from the matrix, so that both the upper and under surfaces of 

 the skull are completely exposed to view. The bone is in a 

 very good state of preservation, and exhibits in great perfec- 

 tion, covering the whole of the upper aspect, the peculiar 

 honeycombed or reticulated structure common to these Laby- 

 rinthodonts. The roof of the mouth is also well displayed, 

 particularly the sphenoid and the vomerine and palatal bones. 



