Huxley — On a new Reptile from the Chalk-marl. 67 



chocolate colotir run vertically and parallel to one another from the 

 serrated edge to the swollen hase, on which they die out. The 

 middle of each intermediate pale brown band exhibits a very 

 delicate dark Kne. 



One of these pale brown bands occupies the middle of each face of 

 the tooth and its apex. On each side of this are six or seven dark 

 bands and as many interspaces. The dark bands correspond pretty 

 nearly, but not exactly, with the summits of the serrations. 



The shape of these teeth is quite different from that of the teeth 

 of Scelidosaurus, which they approach most nearly. 



The most perfect fragment of any of the bones of the extremities 

 appears to be the distal end of a humerus. It presents a division 

 into two condyles by wide and shallow anterior and posterior de- 

 pressions, and the width of the bone in this part, when perfect, could 

 hardly have been less than five inches. It narrows very rapidly, 

 however, and where it is broken, at 3 "6 in. from the dorsal end, its 

 shaft is not more than 1*7 in. wide and as much in antero -posterior 

 diameter. It has a large medullary cavity, the bony walls of which 

 are on the average not more than 0*3 in. thick. 



From the general resemblance of the dermal armour and teeth of 

 this reptile to those of Scelidosaurus, Hylceosaurus, and Polacanihus, 

 it plainly belongs to the same group ; but its teeth separate it from 

 the first genus, and the characters of its dermal armour from the two 

 latter. I propose to call it Aeanthopholis Jiorridus. 



My colleague Mr. Etheridge is good enough to supply me with 

 the following precise determination of the stratigraphical position of 

 the remains. I may add that numerous portions of Ichthyosaurus 

 campylodon have been obtained by Mr. Griffiths " about six feet lower 

 down " than Acanthopholis. 



EXPLANATION OF PLATE V. 



Aeanihopholis horridus, Huxley. 



Fig. 1. a. Side view of one of the spine-like scutes : b. Front view of the same. 

 Fig. 2. a. A more depressed scate seen from above; b. viewed laterally; e. viewed 



from the hinder, or more raised, end. 

 Fig. 3. a. A still flatter scute seen from above ; b. viewed laterally ; c, viewed from 



the hinder end. 



(The preceding figures are one-half the size by nature.) 

 Fig. 4. a. A tooth viewed from one side ; b. with one edge turned to the eye ; c. from 



above. — The outlines give the natural size of the tooth. 



V. — On the Stratigraphical Position of Acantuopbolis 



HORRIDUS (Huxley). 



By RoBT. Etheridge, Palaeontologist to the Geological Survey of Great Britain. 



PEOFESSOE HUXLEY'S communication, relative to the dis- 

 covery of a new Eeptile in the Lower Chalk of the south of 

 England, which he has called Acanthopholis horridus, may be rendered 

 more interesting by a detailed description of its stratigraphical posi- 

 tion and its associated organic remains, a matter of some importance 

 in this case, as few, if any, higher reptilian remains have occurred 



