TRANSACTIONS OF SECTION C. 657 



4. On the Homes and Migrations of the Earliest Forms of Animal Life 

 as indicated by Recent Researches. By Heney Hicks, M.D., F.R.S., 

 F.G.S. 



The author, after giving a history of the finding of zones of animal life at 

 lower and lower horizons in the Cambrian rocks during the past forty years, 

 referred to some recent evidence which points to the extension of similar forms of 

 life over very large areas. That there were many centres of dispersion in different 

 parts of the world seems certain ; but as the migrations of the forms found on each 

 jside of the Atlantic seem to have taken place contemporaneously, the author believes 

 that the original home of these forms must have been at some point in the Atlantic 

 when that basin was much narrower than it is at present. The author then referred 

 to the evidence, showing a gradual development in these earlier forms of life, and 

 to some points bearing on the question of evolution. 



5. On some Vertebrate Remains from the RhcEtic Strata of Britain. {Third 

 Contribution.) By Montagu Browne, F.G.S. , F.Z.S. 



Labteinthodontia. 



Parts of jaws and teeth of a Labyrinthodont Amphibian are found commonly, 

 though very imperfect, in the ' bone-bed' of Aust Clitf, Gloucestershire. So much 

 material has been accumulated that it may be as well to record that ten specimens 

 of the pre-maxilla— showing large ' tusks ' and a serial outer row of smaller teeth — 

 are knovirn to the writer, four of which are in the Bristol Museum, where they are 

 labelled ' Jaws of Enaliosaurians,' and six others, from Aust and Westbury-on- 

 Severn, are in his own possession. One of these was sent as the ' scute of a reptile ; ' 

 and another, before its development from the matrix, was so much like a coprolite 

 as to lead to the inference that others may have been previously passed over. Of 

 the maxilla there are six large portions and several smaller ones, carrying both 

 large and small teeth of two distinct characters. Several large and many small 

 pieces represent the mandible, some, near the symphysis, showing large teeth. Of 

 teeth, both seated upon the bone and broken away, there are a great many examples 

 of all sizes. Five pieces are apparently portions of the palato-vomerine element, 

 carrying large and small teeth. 



Between fifty and sixty specimens are fragments of the jaws, and there are 

 many specimens which are doubtless portions of the elements of the skull and of 

 the thoracic plates. A few portions of limb-bones are doubtfully referable to the 

 Labyrinthodontia. 



The definite determination of the pre-maxilla, portions of the maxilla, man- 

 dible, and some other parts of the Labyrinthodontia, appears' to be a new' record for 

 the Rhfetic of Britain. No speculation is hazarded as yet as to the generic or 

 specific determination of these remains, as if not referable to Metopomurus (Meto- 

 pius) diagiiosticus,^ they appear to have affinities with Trtmatosaurus in the 

 character of the united or single pre-maxilla, and bv the large tusks being internal 

 to the serial mandibular teeth ; on the other hand, the anterior or ' tusk ' teeth are 

 large— some of them f in. in diameter— each with a correspondingly large pulp- 

 cavity, and although apparently simply plicated in the exserted portion, yet at the 

 extreme base the plications of the dentine are complex, and somewhat" resemble 

 those shown in the teeth of Mastodonsaurus Jiigeri as figured by Meyer.^ 



The presence of teeth of two characters— large or Labyrmthodont, and small or 

 ' Saurichthyan '—in the same jaws, together with the characters of the external 

 surface and alveolar palatal extension of the maxilla and of sections thereof, leads 

 to the conclusion, hinted at in the last Report under the heading of Termat.osaurus 

 crocodilinus,^ that ' Saurichtkys' is a non-existent piscine genus, and that jaws 



' Miall, Re2J. Brit. Assoc, 1874, p. 157; but see Lydekker, Cat. Foss. Rep. and 

 Amph., p. 157. 



2 Die Saurier des Muschelkalkes (18i7-55), Tab. 64, fig. 2. 

 ' Montagu Browne, Rep. Brit. Assoc, 1893, p. 749. 

 1894. ^ „ 



