86 ON THE PLACENTAL STRUCTURES OF THE TENREC 



the term ' litis ' as an equivalent for Mustela furo. Breschet 1 , 

 however, is in no way justified in substituting for ' le furet putois' 

 the words ' la belette Mustela / and Daubenton'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 Simiadae (%io) : — 



• Chaque foetus avait deux placentas ronds, poses sur une zone circulaire qui em- 

 brassait le foetus sur le milieu du corps, comme le placentas du Chien et de la 

 Fouine. Les placentas du Furet avaient chacun environ neuf a dix lignes de diametre 

 et une ligne d'epaisseur dans le milieu. Leur face extdrieure e'tait grisatre, et l'in- 

 tdrieure avait une couleur rougeatre. lis n'etaient eloignes l'un de l'autre que d'une 

 ligne par l'un des c6te"s et d'un pouce par l'autre c6te ; ce dernier intervalle e'tait 

 rempli par une sorte de placenta, car la substance qui sy trouvait etait beaucoup plus 

 epaisse que celle du chorion et celle de Vamnios.'' 



Rodentia. 



The following history will show that in the rat, and probably in 

 all other rodents, the three structures which we have called 

 placenta, deciduous serotina, and non-deciduous serotina are as 

 distinct from each other as they are either in the cat or in the 

 tenrec. A female rat (Mtts 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 macerating action 

 of the digestive juice, had its villi hanging free, and presenting an 

 arborescent appearance. Portions of decidua serotina were found 

 in the stomach lying loose by themselves. Some of the placentae 

 had cords of about an inch in length in connexion with them. 



Along one uterine cornu there were found six, and along the 

 other were found three globular masses forming hernial protrusions 

 either into or by the side of the mesometrium, and marking the 

 places of the attachment of the nine foetuses. The cavity of the 



1 'Me'moires de l'lnstitut.,' torn. xix. p. 457. 



