294 PROFESSOR ROLLESTON ON THE 
fied in substituting for ‘“‘le Furet Putois ” the words “‘la belette Mustela ;”’ and Dau- 
benton’s words, which we append, will show that he is scarcely justified in speaking of 
this creature as furnishing an instance of a double placenta, such as that which we find 
in the Old-World Simiade (p. 220), ‘‘ Chaque foetus avoit deux placentas ronds, posés 
sur une zone circulaire qui embrassoit le foetus sur le milieu du corps, comme les 
placentas du Chien et de la Fouine. Les placentas du Furet avoient chacun environ neuf 
a dix lignes de diamétre et une ligne d’épaisseur dans le milieu. Leur face extérieure 
étoit grisdtre, et l’intérieure avoit une couleur rougeatre. Ils n’étoient éloignés l’un de 
V’autre que d’une ligne par l’un des cétés et d’un pouce par l’autre cété ; ce dernier inter- 
valle étoit rempli par une sorte de placenta, car la substance qui s’y trowvoit étoit beaucoup 
plus épaisse que celle du chorion et celle de l’amnios.” 
Rodentia. 
The following history will show that in the Rat, and probably in ail other Rodents, 
the three structures which we have called placenta, deciduous serotina, and non-deci- 
duous serotina are as distinct from each other as they are either in the Cat or in the 
Tenrec. A female Rat (Mus decumanus) was killed after giving birth to nine foetuses. 
Of these, three had been partly devoured by the mother to the extent of one-third or so 
of their whole bodies, beginning in two cases from the head and in the third from the 
tail. The stomach of the mother was found to contain, besides the food furnished to 
her and the portions of the foetuses just specified, the placentas or a great number of 
the placentas which had been in connexion with the nine foetuses. Some of these 
placentas had upon the convex surface a cap of pulpy decidua serotina with a thickened 
border ; in others this cap was removed, and the placenta, from exposure to the mace- 
rating action of the digestive juice, had its villi hanging free, and presenting an arbo- 
rescent appearance. Portions of decidua serotina were found in the stomach lying loose 
by themselves. Some of the placentz had cords of about an inch in length in connexion 
with them. 
Along one uterine cornu there were found six, and along the other there were found 
three globular masses forming hernial protrusions either into, or by the side of the 
mesometrium, and marking the places of attachment of the nine foetuses. A vertical 
section of one of these lateral dilatations, together with the uterine tube to which it is 
appended, is given in Pl. L. fig. 8. The cavity of the uterine tube is covered with a 
corrugated mucous membrane ; at its mesometrial border a funnel-shaped depression, also 
covered with this corrugated mucous membrane, leads down to the hernial protrusion, 
or globular dilatation, which is formed by the non-deciduous serotina (ps) and the 
circular muscular coat (c Mm) with which the utero-placental mucous membrane is more 
intimately connected in the Rodents than in any of the three orders we have as yet 
spoken of, and in the interstices of which much mucous tissue is contained. A pro- 
jecting process (uP) of corrugated non-placental membrane marks the line where a 
