ON ARCHICHTHYS SULCIDENS. 393 



small tooth is situated in front of this. The second large tooth 

 is two inches further back, and the third is one inch and one- 

 eighth behind the second ; the last is therefore three inches and 

 three-eighths behind the first ; but the space between the apices 

 of the first and last large teeth is four inches and a quarter — a 

 distance corresponding very nearly to that between the depres- 

 sions behind the vomerine and last palatal teeth. The smaller 

 teeth vary from three-eighths to about three-quarters of an inch 

 in length ; they are all considerably compressed towards the 

 apex, and have wide cutting - margins ; the lower portion is 

 rounded and grooved, the grooves extending for a considerable 

 way up the crown. 



Abchichthys sulcidens, Hancock and Atthey. 



Some additional remains of this large and powerful fish have 

 recently occurred at Newsham, where the original specimens 

 were obtained that were described some time ago in the " An- 

 nals" (April, 1870). The most important of these recent acqui- 

 sitions is a considerable portion of a crushed head, which, though 

 in a bad and much disturbed condition, shows in a very sa- 

 tisfactory manner the thick, massive character of the bones ; 

 moreover, many of the parts are very well displayed. A large 

 portion of a mandible, measuring upwards of ten inches long, 

 lies in the middle of the mass, with the inner surface exposed, 

 and with the alveolar border turned over ; so that several of the 

 teeth are seen, measuring from three-eighths to four-eighths of an 

 inch in length. This fragment (for, large as it is, it is but a 

 fragment) has lost both extremities. 



The anterior extremity of each mandibular ramus is likewise 

 present on the slab, and has a large laniary tooth in front, and 

 several of the small teeth behind. One of the large teeth is 

 nearly perfect, and measures two inches in length, though the 

 extreme apex is deficient, and is nearly an inch wide at the 

 base. The other laniary tooth has been apparently equally 

 large, but merely its stump remains. The largest of the small 

 teeth are about half an inch long ; the}- appear, however, to 



