16 FOSSIL REPTILIA OP THE 



Genus — Nuthetes, Owen} 

 Species — Nuthetes destructor. 



In a former ' Monograph on the Fossil Lacertian Reptiles of the Purbeck Limestones ' 

 the above genus and species were founded on portions of jaw and teeth, kindly trans- 

 mitted to me by Charles Wilcox, Esq., of Swanage, Dorsetshire. 



In Mr. Beckles' collection further evidence of Nuthetes destructor is afforded by the 

 portions of jaw (PI. II, figs. 13 and 14) and by numerous detached teeth, ranging in size 

 from a length of enamelled crown of 5 mm. to 20 mm, (fig. 15, '^), and with variations 

 in the proportion of length to basal breadth (comp. fig. 15, d, e, with a, b). 



The teeth in the mandibular fragment accord in size and shape with those of the 

 original or type specimen ;^ they are laterally compressed, strongly recurved, and combine 

 a basal fore-and-aft breadth of 3 mm. with the length of 5 mm. (straight). They 

 likewise show the " excavation or longitudinal depression on the side of the base."^ 

 The coronal enamel does not extend over this depression, but is continued along its 

 margins, and to a greater extent on that next the convex border of the crown than on the 

 opposite side. In the portion of jaw, originally figured, with seven more or less perfect 

 tooth-crowns, two of these indicate a longer and more slender shape than the rest. 

 Several detached teeth of this type have been exposed in portions of the ' Feather-bed 

 Marl ' in the Becklesian series. Some of these, exemplifying difference of size, are 

 figured in Plate II, fig. 15. 



In all these tooth-crowns the characteristic fore and hind finely denticulate ridges are 

 discernible, as shown in the magnified view (fig. 16) ; the rest of the enamel is smooth 

 and even, as in the type of Nuthetes destructor. Of this species I am disposed to regard 

 the specimens above described as indicative of the range of size according to growth of 

 individuals rather than as exemplifying specific modifications of the genus. 



Dermal Bones (' granicones '). 



In many portions of the matrix of the ' Feather-bed ' are ossicles of a conical shape, 

 the cone showing various degrees of elevation, with a granulate surface, the base being flat 

 and smooth, or faintly and minutely pitted. These ' granicones ' I regard as dermal bones, 



^ ' Monograph on the Fossil Lacertian Reptiles of the Purbeck Limestones,' Palseontological Society's 

 volume, issued for 1858, p. 31. 18G1. 



2 'Quarterly Journal of the Geological Society,' 1854, p. 120. 



3 lb., ib. 



