PLACENTAL STRUCTURES OF THE TENREC. 293 
and the greater relative abundance of all the other elements, and the smaller conse- 
quent size of the honeycomb vacuoles, may account for the maintenance by it of an 
independent existence up to the period of parturition. It exists, however, in the Cat 
at full time rather as a separable than as a coherent layer. In the Dog it is neither 
coherent nor separable from the placenta’. 
It is difficult to see how, with the honeycomb-like decidua serotina of the foetal Dog 
placed in relation with the mucous membrane of the unimpregnated and unenlarged 
uterus of the bitch as figured by Dr. Sharpey” before one, it is possible to cast the doubt 
upon that observer’s views which M. Robin has done®. It is obvious that when glands 
or follicles are arranged as closely together as in the figure referred to, all increase of 
their calibre must take place by means of outgrowth of interfollicular or interglandular 
substance, and that, admitting the facts which are incontrovertible, the contradiction of 
of M. Robin amounts but to a dispute‘ as to the use of words. Bischoff’s assertion’, 
that the cotyledons of the Roe (Cervus capreolus) are devoid of utricular glands, amounts 
to more than a verbal question; but as Eschricht and Von Baer had noted their 
absence in the similar structures of ordinary Ruminants® many years previously, this 
observation has little claim to be quoted as novel. 
The decidua reflexa can be scarcely said to be present even as a mere rudiment in 
Carnivora. The mucous secretion found exteriorly to the chorion may perhaps be con- 
sidered as homologous with the distal part of what in other orders is a coherent, more 
or less perfectly encapsulating membrane. 
I have not observed, nor do I know, that any observations have been made showing 
that any variations exist as to the relations or degree of development of the allantois, 
amnios, or umbilical vesicle within the class Carnivora. 
Von Baer’s words (J. c. p. 243), ‘‘ Vielleicht weicht das Ei der Sohlenganger, das ich 
nicht kenne in einiger Hinsicht, ab; beim IlItis ist der Giirtel des Fruchtkuchens nicht 
volistandig,” refer in all probability to the description given of the placenta of the 
Ferret by Daubenton, in the ‘ Histoire Naturelle,’ tom. vii. 1758. ‘‘ Iltis”” is ordinarily 
used to denote the Polecat (Mustela putorius) ; but Von Baer may have thought himself 
justified in considering the Polecat and Ferret as of the same species, and using the 
term ‘‘ Iltis ’ as an equivalent for Mustela furo. Breschet’, however, is in no way justi- 
* It would seem from Barkow’s description of the fcetal membranes of a Seal (Phoca vitulina), that the 
decidua serotina possesses both these characters in that animal (Zootomische Bemerkungen, 1851, p. 7). 
* Miiller’s ‘ Physiology,’ translated by Dr. Baly, p. 1575. 
* Robin, /. c. p. 132, “ Les villosités des cotyledons ou du chorion de ’homme et des autres mammiferes tels 
que ruminants, rongeurs, carnassiers, solipédes, et fissipédes, n’enfoncent pas, comme on le dit, leurs subdivisions 
terminales dans les glandes tubuleuses de la muqueuse utérine.”” 
* See also Goodsir, ‘ Anat. and Path. Observations,’ 1845, p. 58; and Henle, ‘ Handbuch der Eingeweidelehre,’ 
1862, p. 462. 
® «Entwickelungsgeschichte des Rehes,’ 1854, p. 22, fig. 43, cit. Kolliker, /. c. p. 170. 
® Von Baer, ‘ Gefassverbindung,’ p. 16. Eschricht, ‘De Organis,’ p. 36. 
* «Mémoires de l'Institut,’ tom. xix. p. 457. 
