PROF. W. TURNER ON THE PLACENTATION OE THE LEMURS. 
579 
action of the salt in which the carcass had been for so many months preserved after 
the animal had been shot, the uterus had become so much contracted that it required 
some hours steeping in water before it was fit for drawing and dissecting. As the ovum 
could have been in only a very early stage of development, its delicate tissues had 
probably so shrivelled up that it entirely escaped notice when the uterus was opened. 
There could, I am sure, be no question that the uterus was gravid, for not only was the 
one horn more distended than the other, but the folds of its mucous membrane were 
bigger, much more convoluted and subdivided than is the case with the folds of the 
mucosa in the non-gravid uterus. 
General Observations on the Placentation of the Lemurs. 
Several eminent zoologists, in classifying the Mammalia according to their placental 
characters, have placed the Lemurs, along with the Insectivora, Eodentia, Chiroptera, 
Apes, and Man, in the Discoplacentalia. So far as I have been able to examine the 
literature of the subject, no description of the dissection of a gravid uterus of a Lemur 
containing a disk-shaped placenta has been put on record. Indeed, until M. Alphonse 
Milne-Edwards published his brief Memoirs on their placentation, no gravid uterus of 
a Lemur appears to have been examined. Because the Lemurs corresponded to the 
Apes in the opposability of the thumb and great toe, in the presence of incisor, canine, 
premolar, and molar teeth, and in the pectoral position of at least two of the mammae, 
and to the Insectivora in the pointed tubercles on the crowns of the molar teeth, it has 
apparently been assumed that they must also correspond with the Apes and Insectivora 
in the possession of a disk-shaped placenta. The observations of M. Alphonse Milne- 
Edwards have, however, clearly proved that the placenta in the Lemurs is not disk- 
shaped ; and though he applied to it the name bell-shaped, he yet concluded that it 
had affinities to the zonary placenta of the Carnivora. 
From the description which I have • given in this Memoir of the arrangement and 
structure of the maternal and foetal parts of the placenta in the several genera examined, 
it will I think be at once admitted that not only is the placenta in the Lemurs not 
discoidal, but that it cannot be regarded as a modification of the zonary form of placenta. 
Both in form and structure the placenta in the Lemurs is without doubt a diffused 
placenta. To make this important conclusion clearer, I shall summarize the facts 
which prove this to be the character of the placentation. 
a. By gentle traction the ridges and villi of the chorion can be drawn out of the sulci 
and crypts of the uterine mucosa so that the foetal and maternal parts of the placenta 
can be readily and completely separated from each other, as can be done in the diffused 
placenta of the Pig, Mare, or Cetacean, but as cannot be done either in the discoid 
placenta or in the zonary placenta of the Carnivora. 
b. The chorion is prolonged from the tip of one cornu, through the corpus uteri, to 
the tip of the opposite horn, as in the uniparous Mare and Cetacean, and is not, as in 
the uniparous Seal, limited to the side of the uterus in which the foetus is developed. 
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