1853.] COLES — SKIN OF THE ICHTHYOSAURUS. 81 



are as many points of dissimilarity as of resemblance to any of these 

 structures. From the great approximation of the Ichthyosaurus to 

 the Ichthyic form, as particularly evidenced in its general contour 

 and its biconcave vertebrae, it need be no matter of surprise to find 

 a structure analogous to scales in this animal. iVnd when we regard 

 the strange and anomalous coverings of the Fishes of the Palaeozoic 

 period, we might be led to expect that even in animals of a later sera, 

 there should be a great departure from ordinary types, and a blending 

 together of the peculiarities of diverse structures. Although, then, 

 none of the usual tegumentary appellations seem to me strictly appli- 

 cable, I am not disposed to offer another to the overburthened list of 

 scientific names, but would prefer calling these bodies setiform or 

 bristly scales. 



I am not able to offer any satisfactory conjecture as to what was 

 the real condition and complete structure of the integument of the 

 living animal. The brief notices by Dr. Buckland and Professor 

 Owenf, with the slight addition to our knowledge on the subject 

 which this paper professes to offer, leave much further information 

 to be desired, and a large scope for future research. 



In two uncleaned masses of the bones of Plesiosauri, I have not 

 succeeded in detecting any analogous structure. 



I have been rather diffuse in the detail of the circumstances attend- 

 ant on the discovery and identification of these minute structures, 

 partly because I wished to obviate any conjecture that they might 

 be merely accidental extraneous bodies, and partly because they 

 furnish an instance of the importance of not overlooking apparently 

 insignificant objects, and suggest an argument for the more minute 

 investigation of the material in which fossils are found imbedded. 



I may add, that by the courtesy of Mr. Waterhouse, of the British 

 Museum, I inspected, with him, many Saurian bones in that Institu- 

 tion, but we found they had been so well cleaned that no traces of 

 the skin could be discerned. I met with no better success among 

 the large specimens in our own Museum, but in a small Ichthyosaurus 

 from Lyme Regis, presented by Sir H. De la Beche, a considerable 

 portion of the skin exhibiting these peculiarities has been preserved, 



Mr. C. Moore, of Ilminster, has also kindly communicated some 

 fragments which show sufficient elements of a similar structure, to 

 satisfy Prof. Quekett and myself of the presence of these bodies, but 

 as they occur in hard limestone, they cannot easily be detached, or 

 very readily recognized. Still more recently, Mr. Gough, of Kendal, 

 has sent me portions of the skin of an Ichthyosaurus in his collection, 

 which display these forms very perfectly and distinctly. 



DESCRIPTION OF PLATE V. 



Fig. 1. Subvertebral bone of Ichthyosaurus (one of the wedge-bones of the cervical 

 vertebrae), partially coated with the remains of the skin. Nat. size. 



Fig. 2. A patch from the lower left-hand corner (*) of Fig. 1 ; seen by reflected 

 hght ; magnified 25 diameters. 



Figs. 3, 4, 5. Setiform scales ; seen by reflected light ; magnified 50 diameters. 



Figs. 6-13. Setiform scales, seen by transmitted light ; showing more or less of 

 the component elements of their structure ; — fig. 6, magnified 100 dia- 

 meters ; figs. 7-13, magnified 45 diameters. 



tBridgewaterTreatise,vol.ii. p.22; and Trans. Geol. Soc. Ser. 2, vol. vi. Tp.l99 ei seq. 



