134 CONTRIBUTIONS TO ZOOLOGICAL PATHOLOGY. 
brim of the acetabulum, and was otherwise imperfect ; but the Ha- 
versian gland was large and well developed.” 
In both of these cases the external appearances, during the 
movements of the joint, were very similar to each other : short- 
ening of the entire limb, especially during motion ; approximation 
of the great trochanters to the spine and crest of the ilium, and 
inversion of the foot and toes ; exhibiting, in short, all the appear- 
ances connected with a dislocation of the head of the bone directly 
upwards*, or upwards and backwards. 
III . — Congenital Absence of the Round Ligament. 
This form of malformation by congenital deficiency is by no 
means of unfrequent occurrence, both in man and in the lower 
animals ; and, indeed, of all the ligaments in the structure of the 
skeleton, this, the round ligament of the hip-joint, is that which 
has been most frequently noticed as being wanting, from conge- 
nital defect. Its absence in man has been noticed under these 
circumstances, by many anatomists, from the time of Gengat down 
to the present day ; and it is well known to comparative anato- 
mists that its absence in many of the mammalia is so regular, that 
this condition of the joint is looked upon as the normal structure. 
“ It is not usually possessed by the orang-outan (though it is 
found in the chimpanzee and gibbons), and its absence has also 
been noticed in the elephant, the sloth, the seal, the enhydra, and 
the ornithorinchus. It has also been reported as being wanting in 
the tucutuco (Ctenomys Magellanicus, Bennet), though it has not 
been substantiated by other anatomists J.” 
Instances of its absence in those of the mammalia that come 
under the notice of the veterinarian have been seldom reported. 
I have not as yet seen one case of such deficiency in my zoological 
investigations ; but, through the kindness of Professor Dick, I have 
been furnished with an account of three cases of its occurrence in 
the horse, which have come under his notice. “ Within the last 
four years,” says he, “ three cases of total absence of the round 
ligament of the hip-joint, in one side only, occurred in my dis- 
secting-rooms here. The subjects of all these cases were aged 
horses, which were obtained either at the knacker’s yard, or 
were purchased, as usual, for dissection, as old worn-out horses. 
All of them seemed to have undergone much work, as common 
* This form of dislocation can only occur where there is deficiency in the 
cotyloid brim and ligament, which here existed, 
t Genga, Anatomica Chirurgica, 8vo, Rome 1687. 
f Martin’s Nat. Hist, of Quad., p. 100. 
