Tertiary Vertebrata of the West. 419 



of the upper molars. Enough of the skeleton of M.ferox is known 

 to show that its nearest living ally is probably Thylacynus ; but it 

 differs from Marsupials in having a patella. It is about as large as 

 a Sheep. The remaining American genera of Creodonts are Dissacus, 

 Sarcothraustes and Mesonyx. The latter genus has some resemblance 

 to Hycenodon, but more to Amblyctonus. The claws are flat like those 

 of Seals ; but the structure of the ankle suggests that the type was 

 not exclusively aquatic. Mesonyx is thought to have lived on Turtles. 



M. ossifragus was as large as a large-sized American Black Bear 

 with the fore-limbs much shorter than the hind-limbs, giving much 

 the aspect of a huge Babbit, except that the tail was long. It was 

 one of the largest Eocene flesh-eaters. 



In this review we have attempted to give some idea of the varied 

 organization comprised in the Bunotheria. The conception of this. 

 group is the most original contribution to mammalian classification 

 which has been made for a long time. The group is almost as diffi- 

 cult to realize, as would be a conception of the Marsupialia, if Marsu- 

 pials were only known in a fossil state. Some exception may be 

 taken to the term order, by which the Bunotheria is indicated, for 

 the group is rather a lower division of the placental subclass ; which 

 the author would compare to the Marsupialia in the variety of 

 organization it includes, while he believes it to have developed 

 simultaneously with the Marsupials, or even to have been an older 

 group. The classification has necessarily grown out of the affinities 

 which the described families of Mammals have with each other, 

 rather than with surviving groups ; and although we cannot pro- 

 nounce a decided conviction on the importance of this great general- 

 ization without an examination of the specimens on which it is 

 founded, the principles on which it is evolved are sound. If we 

 recognized the Creodonta and other groups as allied to existing orders 

 of Mammals, but distinguished by their smaller brains, and less 

 specialized organization, then the existence of the Bunotheria becomes 

 not only a convenience in classification, but a generalization which 

 will direct research. H. G. Seelet. 



{To be continued.) 



II. — Catalogue of the Blastoidea in the Geological Depart- 

 ment of the British Museum (Natural History), with an 

 Account of the Morphology and Systematic Position of the 

 Group, and a Revision of the Genera and Species. By 

 Robert Etheridge, Jun., and P. Herbert Carpenter, D.Sc., 

 F.R.S., F.L.S. 4to. pp. xiv. and 322. Illustrated by Twenty 

 Lithographic Plates and Twelve Woodcuts. (London, 1886, 

 Printed by Order of the Trustees.) Price 25s. 



WE know not whether it be due to the beneficial effects of trans- 

 plantation, but there has certainly been a steady issue of 

 publications in connection with this Department since its removal, in 

 1880, from Great Russell Street, Bloomsbury, to the new soil of 

 Cromwell Road. 



