ttt i te & eae 
aay mame é 1—__ eeee 
agg Fe eae a 
145 
Dr. Melville then communicated orally the first part of his paper 
“‘On the Ideal Vertebra.” He commenced by defining this as “ the 
most complete possible segment of the endo-skeleton,” or in the 
words of his friend Mr. Maclise, ‘“ the plus vertebral quantity ;”” and 
it was illustrated by a diagram showing the body, neural arch and 
spine, and two concentric arches or circles below, the inner one con- 
sisting of three elements, to which he gave the names hemapophyses 
and hemal spine, and the outer one formed by the ribs and sternum. 
He had arrived, he said, at this idea by observing the inner or true 
hemal arch coexisting with the costo-sternal arch in many animals, 
and referred especially to the skeleton of a lizard in the British Mu- 
seum as illustrating his discovery; and regretting that the laws of 
that Institution prevented his exhibiting it at the Meeting, he showed 
the hemapophyses in enlarged diagrams of the cervical and dorsal 
vertebrz, and contrasted his ideal vertebra with diagrams of those 
given by Geoffroy St. Hilaire and Professor Owen. The bones, 
which Dr. Melville stated Sir P. Egerton had rediscovered in the 
Ichthyosaurus, and called ‘ wedge-bones,’ were the true hemapo- 
physes, and he referred to a work by Camper, in which the cervical 
heemapophyses had been previously described. 
The bone which had been called the body of the atlas was the 
hemapophysis of the occipital vertebra; and the ‘ odontoid process’ 
was the true body of the atlas. The bones which Professor Miiller 
had defined as the inferior transverse processes in fishes, and which 
Professor Owen had called ‘ parapophyses,’ were the true hemapo- 
physes, and the term ‘ parapophyses’ ought to be abolished, as it 
had been applied to several distinct elements. True hemapophyses 
were sometimes autogenous, sometimes exogenous. 
Adverting to the pleurapophyses or pleural elements of the ver- 
tebre, Dr. Melville alluded to Miller and Thirles’ discovery of these 
in the lumbar and sacral region, where they had been called ‘ trans- 
verse processes, and he exhibited the sacral vertebra of an ‘ iguano- 
don,’ showing the articular cavity for the sacral rib. 
With regard to the exogenous processes of the vertebrae, which 
Professor Owen had called ‘ diapophyses,’ Dr. Melville exhibited the 
vertebral columns of some quadrupeds, showing that they sent off 
a process backwards in the dorsal vertebree, and were continued into 
the lumbar region by such posterior processes, and not by the pro- 
cesses which Professor Owen had called diapophyses in the lumbar 
region. Understanding that Professor Owen had proposed names 
for these mere subdivisions of the diapophyses, Dr. Melville strongly 
deprecated the overloading this difficult part of anatomy with unne- 
cessary names. He also animadverted on Cuvier and M, De Blain- 
ville for having neglected to describe these modifications of the trans- 
verse processes. Dr. Melville pointed out in the vertebre of an 
ant-eater and armadillo the processes which project forwards from 
the anterior zygapophyses, and which he believed Professor Owen 
called the ‘ epizygapophyses "(the Professor here stated that he had 
given that name to the superior articular processes in serpents, which 
were not homologous with the processes alluded to by Dr. Melville, 
