148 INTESTINAL STRUCTURE OF ICHTHYOSAURUS. 



On the shore at Lyme Regis, these Coprolites are so 

 abundant that they lie in some parts of the lias like pota- 

 toes scattered in the ground ; still more common are they 

 in the lias of the Estuary of the Severn, where they are 



Society of London, 1829, (vol. iii. n. s. part i. p. 224, with three 

 plates.) 



" In variety of size and external form, the Coprolites resemble oblong 

 pebbles or kidney-potatoes. They, for the most part, vary from two to four 

 inches in length, and from one to two inches in diameter. Some few 

 are much larger, and bear a due proportion to the gigantic calibre of tlie 

 iartrest Ichthyosauri; others are small, and bear a similar ratio to the more 

 infantine individuals of the same speclesj and to small fishes : some are flat 

 and amorphous, as if the substance had been voided in a semifluid state; others 

 are flattened by pressure of the shale. Their usual colour is ash-gray, some- 

 times interspersed with black, and sometimes wholly black. Their sub- 

 stance is of a compact earthy texture, resembling indurated clay, and 

 having a conchoidal and glossy fracture. The structure of the Coprolites 

 at Lyme Regis is in most cases tortuous, but the number of coils rs very 

 liiiequal ; the most common number is three : the greatest I have seen is 

 six : these variations may depend on the various species of animals froni 

 which they are derived; I find analogous variations in the tortuous intestines 

 of modern Skates, Sharks, and Dog-fish. Some Coprolites, especially the 

 small ones, show no traces at all of contortion. 



" The sections of these fcEcal balls, {see PL 15, Figs. 4, and 6,) show 

 uieir interior to be arranged in a folded plate, wrapped spirally round from 

 the centre outwards, like the whorls of a turbinated shell ; their exterior also 

 retains the corrugations and minute impressions, which, in their plastic 

 state, they may have received from the intestines of the living animals. {See 

 PL 15, Figs. 3, and 10 to 14.) Dispersed irregularly and abundantly through- 

 out these petrified foeces, are the scales, and occasionally the teeth and bones 

 of fishes, that seem to have passed undigested through the bodies of the 

 Saurians; just as the enamel of teeth and sometimes fragments of bone, arc 

 found undigested both in the recent and fossil album grfficum of hyjenas. 

 These scales are the hard bright scales of the Dapedium politmn, and 

 other fishes which abound in the lias, and which thus appear to have 

 formed no small portion of the food of the Saurians. The bones are chiefly 

 vertebrse of fishes and of small Ichthyosauri ; the latter are less frequent 

 than the bones of fishes, but still arc sufficiently numerous, to show that 

 these monsters of the ancient deep, like many of their successors in our 

 modern oceans, may have devoured the small and weaker individuals of ihe;.r 

 own species " 



