PURBECK CROCODILES. 641 



should last so long as to render it needful for the reptile to take a fresh breath, it can 

 protrude its prominent snout from the surface of the river, and inhale a current of air 

 which will traverse the long meatus and enter the glottis by the chamber common to 

 nose and windpipe, which is shut off from the mouth by the above-described structures. 

 We have no ground for inferring this faculty and mechanism of soft parts from the bony 

 palate in amphicoelian Crocodiles ; the difference in its size and position are such as 

 to have deceived both Bronn and De Blainville as to the position and homology of the 

 palatonares in Teleosaurus) 



The subjects of the following sections bear unexpectedly, and in an interesting 

 degree, on another objection, raised during the discussion at the Geological Society of 

 London, on the topics treated of in pp 636 — 640. The objection was, that " warm- 

 blooded animals did actually exist contemporaneously with the Mesosuchian Cro- 

 codiles." ° As the only examples of the Mammalian class of which I was cognisant 

 were the subjects of the undercited Monograph,' and a few other species of like dimi- 

 nutive size, it did not seem to me to affect a question exclusively bearing upon large 

 Mammalian quadrupeds. It seems, however, that the Crocodiles which most abounded, 

 if we may judge from the proportion of their fossil remains in the fresh-water deposits of 

 the ' feather-bed ' subdivision of the Purbeck series, were related in size to their con- 

 temporary diminutive ]\Iammals. The Spalacotheres, Peralestes, Stylodons, Triconodons, 

 &c., may well have been the prey of the dwarf Crocodiles of the locality. For these 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 Marsupials. 



At the first aspect, detecting in the scattered groups of scutes in the Purbeck shales 

 submitted to my inspection, specimens showing the peg (PI. 45, fig. 3, d) and groove 

 (ib., fig. 4, 6), it seemed as if remains of some young specimens of Goniopholis were 

 so exposed. The condition, however, of two of the skulls (PI. 44, figs. 1 and 3) 

 enabled a comparison to be made which determined their specific and, by their den- 

 tition, generic distinctions from both Goniopholis and PefrosucJius. The number of 

 maxillary and mandibular specimens, of which several are figured in PI. 44, exem- 

 plified a degree of constancy in size which begat a conviction that such was a character 

 of the species; and, diminutive as were the Reptilia which have supplied the subjects 

 of both plates, their characters were indisputably those of the Order Crocodilia. 



One of them, by the size and shape of certain teeth, came nearer to Goniopholis, 

 another by the same character resembled Petrosuchus, but the differential characters 

 were such as could not have been obliterated by growth or age. 



A third form of Crocodilian made a nearer approach in one of the species 

 (PI. 42, fig. 2) to the average size of the broad-faced genera. A fourth (ib., fig. 1) 



* ' Abhandlungen iiber die Gavial-artigen Reptilien der Lias-formation,' fol., 1841, pp. 12, 16, 24, 



2 Hulke, J. W., ' Quarterly Journal of the Geological Society,' May, 1878, p. 428. 



^ " Ou the Fossil Mammalia of tlie Mesozoic Formations," Palaeontographical Soc. Volume for 1871. 



