DWARF CROCODILES AND DIMINUTIVE MAMMALS. 149 
the eggs and newly hatched brood, of the cold-blooded amphibious 
giant. 
When, therefore, my cogitations had been turned to any possible 
relations of a Phascolothere* or a Triconodon* to the amphicelian 
Crocodilia of the Oolitic or Wealden periods, I thought of the dimi- 
nutive contemporaneous mammals as reducers of the numbers of 
such Crocodiles, assuming that the reptiles may have sought the 
banks or shores to oviposit, and that their eggs and wriggling brood 
may have tempted the small predatory marsupials, as those of the 
proccelian Crocodiles do their contemporaneous species of Herpestes. 
Pursuing, however, my researches on the Crocodilia of the Pur- 
beck series, I have come, as I believe, upon a relation of them to 
their contemporary diminutive mammals at once most interesting 
and unsuspected. The Spalacotheres, Peralestes, Stylodons, Trico- 
nodons, &c. of the freshwater deposits of the ‘ Feather-bed ” 
may well have been the prey of the Crocodiles of the period; for 
these Crocodiles were reduced to dimensions which forbade them 
to disdain such succulent morsels, and, at the same time, they 
were suitably armed and limbed for the capture of the little mar- 
supials. 
The characters of one of these dwarf Crocodiles I now propose 
briefly to submit to the Geolegical Society; fuller details and 
illustrations of this and other small crocodilian genera and species 
will appear in the forthcoming volume of the Paleontographical 
Society. 
The subjects of the annexed Plate (Pl. IX.), all of the natural 
size, are selected from numerous evidences of the species, which I 
propose to name Theriosuchust pusillus. 
These and other Crocodilian evidences of the Purbeck period have 
been brought to light, or completely exposed, by operations upon 
the residuary slabs of “‘ Feather-bed ” marl which accompanied the 
Becklesian collection to the British Museum, when the negotiations 
for the purchase of the whole were concluded. 
They are very numerous, chiefly consisting of scattered teeth, scutes, 
vertebrae, and detached limb-bones, but likewise of a few skulls and 
mandibles, and, in one or two instances, of considerable portions of 
naturally connected skeletons. The scattered parts associated with 
these have served for the ascription to their several species of 
answerable bones, teeth, and scutes not so associated. 
At the first aspect, detecting in the seattered groups of scutes speci- 
mens showing the peg (Pl. IX. fig. 10, a) and groove (fig. 11, 6), it 
seemed as if remains of some young specimens of Goniopholis had 
been brought to light. The condition, however, of two of the skulls, 
one of which has yielded the subjects of figs. 1, 2, 3, Pl. 1X., enabled 
a comparison to be made which determined their specific and, by 
* ‘Researches on the Fossil Remains of the Extinct Mammals of Australia,’ 
&c. 4to, 1877, vol. i. p. 16, pl. i. figs. 26, 26a. 
+ Op. cit. vol. i. pp. 58, 64, pl. iii. figs. 7, 7a, 11-19. ; 
t Gr. Onpior, wild beast ; covxos, Egyptian name of crocodile. 
