4 PROF. FLOWER ON THE SKULL OF A XIPHODON. [Jan. 4, 



better preserved than any other part of the body, that extuiet forms 

 of the group to which this one is allied have been characterized. 

 The anterior portion of the skull has also been broken off close to the 

 ])remaxillary suture, and consequently is wanting in the specimen. 



Before proceeding to the description of the skull, the question 

 naturally arises — What inference can be drawn from the condition of 

 the fossil and its matrix as to its probable origin ? Several experi- 

 enced palaeontologists to whom it was shown while still partially 

 imbedded, declared that they knew of no fossil remains in a cor- 

 responding condition ; and on comparing it with all the Mammalian 

 specimens from every part of the Avorld, contained in the British 

 Museum, not one was found agreeing with it. 



It certainly approximates very nearly in most of its characters to 

 the curious '"'box stones" of the Suffolk Crag, to which Mr. Ray 

 Lankester directed attention in the ' Quarterly Journal of the Geolo- 

 gical Society' for 18/0 (p. 499), though less ferruginous in colour 

 than they generally are. If this suggestion should prove to be 

 correct, it will confirm the indication as to locality mentioned above. 

 The "box stones" are evidently waterworn aggregations of sand- 

 stone, generally, though by no means invariably, surrounding some 

 organic body, and are remnants of a broken-up formation of an 

 earlier age than the Red Crag in which they are now found. They 

 are considered by Mr. Lankester, from a comparison of the mol- 

 luscous fossils found in them, to be of " Diestien " age, or approxi- 

 mately equivalent to the so-called "Black Crag" of Antwerp ; but, 

 as will be mentioned hereafter, the zoological characters of the present 

 specimen indicate a much greater geological antiquity. 



The skull is that of a rather young animal, as shown by the still 

 open suture between the basioccipital and the basisphenoid bones ; 

 but (at least in the case of existing Ruminants) this sign of imma- 

 turity remains some time after all the permanent teeth are in place, 

 as appears to have been the case in the present specimen. 



The cranium differs most notably from that of all existing species 

 of Ruminants in the breadth and flatness of the frontal region be- 

 tween the orbitci, the sudden contraction behind the orbits, and the 

 large extent of the temporal fossae, which is increased by well- 

 marked sagittal and occipital crests. Hyomoschus is that to which 

 it comes nearest ; indeed, if we could imagine a larger animal of the 

 Traguline type {i. e. an animal with a more lengthened head, and 

 greater surface for the implantation of teeth and for the attachment 

 of muscles, without corresponding increase of size of the brain-cavity 

 and orbits — the modifications, in fact, which always occur in larger, 

 as compared with smaller, members of a natural group), we should 

 obtain a form closely resembling the present skidl. Its special pecu- 

 liarity would still be the flatness and width of the interorbital region 

 above, in consequence of which the cavities of the orbits look directly 

 outwards, instead of upwards and outwards as in HyomoscJms. 



The sides of the face in front of the orbits are flat, as in the Tra- 

 gulidae and in many true Ruminants, without any sign of depression 

 for a suborbital gland ; but further forward, commencing just bes 



