1887] : Embryology. : : 587 
a tiny puppy. The ears are simple, round holes, without a 
conch, and the eyeballs are barely half a millimetre in diameter. 
Another species, H/. glaber, was described by Rüppell forty years 
ago. It is a burrower, the skin passing across the mouth inside 
the incisors. 
EMBRYOLOGY.: 
Suggestion respecting the Epiblastic Origin of the Seg-* 
mental Duct.—In a recent paper? with the above title, Prof. 
A. C. Haddon, of Dublin, offers a very suggestive explanation 
È 
Dr. Perényi observed the same mode of development to obtain 
in Rana esculenta and Lacerta viridis3 
“The origin of the segmental duct from the epiblast being 
now known to occur in Elasmobranchs, Anura, and Rodents 
we are justified in assuming that this is a general and probably 
primitive mode of formation. With the above-mentioned ex- 
somatic meso 
e duct arises, in the Rodents, as a linear proliferation of 
the epiblast, in the region opposite to the intermediate cell-mass 
_ (‘ Grensstrang’ of Hensen). Flemming _ out that the area 
is of riebi length, not even being symmetrical. The separa- 
tion of this solid cord of cells from the piis takes place from 
before backwards, and first occurs at a time when the meso- 
blastic somites are still entirely continuous with the ventral 
ERPE and splanchnic) mesoblast. Hensen, Spee, and Flem 
conjectured that ~*~ primitive kidney is itself déweloped 
kom the epiblast in these mammals; but of this they produce 
t Edited by Prof. JoHN A. RyDER, Biological Department, University of Penn- 
irna omer elphia. 
fe entific Proceedings of the Royal Dublin Society, v., pt. vi., 1887, pp. 
wie [The 2 pl; xe would here, for the first time, record the fact that he has found the 
anterior ends of the segmental ducts intimately connected with the epiblast in young 
embryos of the catfish (Amiurus corer Se that the mode of origin of the seg 
mental duct spoken of above very probably applies also to the Teleostei.] 
