The Birth-period of Trichosurus vulpecula. 79 



to a publication of the results. For this welcome kindness my thanks 

 may be here expressed. 



The two embryos are described and their degrees of development 

 recorded in the following pages, and in an appended table. The 

 embryos were chosen out of a fair series by Dr. Broom himself with 

 a view to my special requirements. No better choice could conceiv- 

 ably have been made; for, while the one embryo (A) was a uterine 

 ■specimen only slightly younger than one newly-born, the other (B), 

 on the testimony of Dr. Broom — and this was confirmed by the 

 sections — had only recently been born , certainly not more than 2 

 or 3 hours. In neither case were the membranes preserved, and thus 

 no examination of them could be made. I have, however. Dr. Broom's 

 assurance, that in this form no allantoic placenta is developed, a 

 point upon which it is necessary to be certain in view of Hill's dis- 

 covery ^) of such a placental connection in Perameles obesula. In the 

 younger embryo the remains of the membranes, chiefly of the amnion, 

 were still attached, and in the one newly-born the torn remnants of 

 the umbilical cord were still present. 



Description of the uterine Embryo. 



Embryo A, uterine specimen with remains of membranes (Fig. 1, 

 PL 4). Greatest length in the preserved condition 14 mm, N. L. about 

 12,5 mm. 



Externally. The head is much bent. The snout is marked. 

 No lachrymal grooves are visible, a circumstance explained by the 

 sections. The lips are fused together 2) at the sides. The mouth is 

 open and the tongue projects. The digits are well-marked, especially 

 those of the fore-limb, and in the latter are clawed. The arms are 

 flexed, but not as markedly as those of the older embryo. The hind 

 limbs are nothing like as far developed as the anterior appendages, 

 the digits of the foot are only barely indicated, the limb itself is not 

 flexed. These latter are points, which have struck every student of 

 marsupial embryos, and they have been commented upon by Meckel, 

 Owen and others. 



1) Hill, J. P., Prel. note on the occurrence of a placental con- 

 nection in Perameles obesula etc., in : Proc. Linn. Soc. N. S. Wales, 

 V. 10, p. 578—581, 1895. 



2) As originally described by W. Leche, but wrongly stated to 

 first occur after birth. 



