484 Geological Society. 



incisors, convex above the canines and molars, and then straight to 

 beneath the orbits. The alveolar border of the mandible is concealed 

 by the overlapping teeth of the upper jaw ; its s}TQphysi8 is deep, 

 slanting backward, and destitute of any trace of suture ; the length 

 of the mandible is 3| inches, which was probably the length of the 

 skull. The incisors are ?^, and the molars probably ^ or ^^, all 

 more or less laniariform. The length of the exsorted crown of the 

 upper canine is 12 millim. ; the root of the left upper canine was 

 found to be twice this length, extending upwards and backwards, 

 slightly expanded, and then a little narrowed to the open end of the 

 pulp-cavity. There is no trace of a successional canine ; but the 

 condition of the pulp-cavity and petrified pulp would seem to indi- 

 cate renewal of the working part of the canine by continuous 

 growth. The author infers that the animal was monophyodont. 

 JSlurosaurus was said to be most nearly allied to Lycosaurus ; but 

 its incisor formula Ls Dasyurine. 



AVith regard to the characters of the Theriodontia the author 

 remarked that we may now add to those given in his 'Catalogue 

 of South African fossil Reptiles,' that the humerus is perforated 

 by an entepicondylar foramen, and the dentition monophyodont. 



April 27, 1881.— Robert Etheridge, Esq., F.E.S., 

 President, in the Chair. 



The following communication was read : — 



" On Fossil Chilostomatous Bryozoa from the Yarra-Yarra, 

 Victoria, Australia." By Arthur William Waters, Esq., F.G.S. 



The author gave a descriptive list of seventy-two species of Bryozoa 

 belonging to the suborder Chilostomata, from a lump of clay obtained 

 by Mr. Allen from the ncighboiirhood of the Yarra-Yarra river. 

 The specimens are fragmentarj-, but in excellent preservation. 

 There are eight species of Catenicella, a genus unknown in the 

 fossil state until quite recently, when 'Sir. Bracebridgc Wilson de- 

 scribed twelve fossil species, none of which are known living ; two 

 of the Yarra-Yarra species still live in the Australian seas ; and one 

 of these also occurs in the Geological Society's collection from Mount 

 Gambler. Among the most interesting of all the specimens de- 

 scribed by the author is a Catenicella consisting of long internodes, 

 with a double row of cells in each internode. The short-beaded 

 Coteniceihe now living have probably been developed from forms 

 with long internodes, MicroporelJa is also well represented by 

 some interesting forms, which make it necessary to widen the de- 

 finition of the genus, A very interesting CeUaria with subglobular 

 internodes explains the Cretaceous fossil called Eschara usjjasia by 

 d'Orbigny. 



Of the Chilostomata found in this deposit thirty-nine are con- 

 KJdeied new, although this number may have to be reduced ; nineteen 

 are now found living ; seven coiTCspond with those from the fossi- 

 liferous beds of Orakei Bay, New Zealand, described by StoLiczka ; 



