ANNIVERSARY ADDRESS OF THE PRESIDENT. XXXlil 
species of mammal belonging to the section of hoofed quadrupeds, 
and forming the type of a new genus to which he gives the name of 
Dichodon. 
In another communication Professor Owen notices the occurrence 
of the fossil remains of the Megaceros hibernicus (commonly known 
as the ‘Irish elk’) and of the Castor europeus in the pleistocene 
deposits forming the brick-fields at Ilford and Grays-Thurrock, Essex, 
thus confirming his statements as to the occurrence of the remains of 
the so-called Irish elk in England. He also remarks that the re- 
mains of the Megaceros, found in England, have been mistaken for 
those of Bos, and points out the difference between the teeth of the 
great Bovines and Megaceros. The teeth of the Bos longifrons being 
smaller than those of Megaceros are readily distinguished by their 
size. 
Professor Owen observes that the Bos longifrons coexisted with 
Megaceros in Ireland, and with Megaceros, Rhinoceros, Elephas, 
Hyena, &c. im England, and that the remains of Bos longifrons 
have been found in ancient places of sepulture, and are so associated 
with British and Roman works “as to leave little doubt of its having 
survived, as a species, many of the mammals with which it was asso- 
ciated during the pleistocene period.” The Professor conceives that 
as yet no good evidence has been adduced to show the coexistence of 
man and the Megaceros. 
We have also to record the reading of another communication to 
the Society by our colleague, Professor Owen, one entitled “ A de- 
scription of teeth and por tions of jaws of two extinct Anthracotherioid 
quadrupeds, Hyopotamus vectianus and H. bovinus, discovered by 
the Marchioness of Hastings in the eocene deposits of the N.W. 
coast of the Isle of Wight, with an attempt to develope an idea of 
Cuvier’s on the classification of pachyderms by the number of their 
toes.” After a careful detail and comparison of teeth, the Professor 
points to a general type of configuration (‘‘a quadrate crown with 
four principal pyramidal and more or less triedral lobes divided by 
deep valleys, not filled up by cement, but in some genera interrupted 
with minor tubercles and ridges,’’) which ‘characterises a great 
natural group of Ungulata, most of the members of which are ex- 
tinct, but which tend to fill up, i the zoological series, the wide in- 
terval that now divides the Peccari or the Hippopotamus from the 
Ruminants.” “The generic or subgeneric modifications of struc- 
ture,’ adds Professor Owen, “at present recognised in this great 
natural group, are signified By names given to the partially restored 
genera :— 
*< Anthracotherium. 
“ Hyopotamus. 
“« Merycopotamus. 
* Hippohyus. 
“ Cheropotamus. 
“« Adapes. 
** Dichodon. 
“« Hyracotherium. 
VOL. IV.—PART I. ¢ 
