1880.] Prof. Owen. On the Ova of Echidna hystrix. 407 



the small intestine is independent of the relative frequency either of 

 the glands of Lieberkuhn, or of those of Brunner, bat appears to be 

 correlative with the distribution of Peyer's glands. 



(8.) In the transition from colloidal starch to readily diffusible and 

 easily assimilated dextrose, the actions of the pancreas and of the 

 Peyer's glands are mutually dependent and complementary. 



The pancreas readily breaks down the starch to maltose, but is 

 capable only of a very slow conversion of the resulting maltose to 

 dextrose. The Peyer's glands on the other hand, whilst almost 

 powerless upon starch itself, take up the work at a point where the 

 pancreatic juice almost ceases to act, and so complete the conversion 

 of starch into dextrose. 



V. " On the Ova of the Echidna hystrix." By Professor OWEN, 

 C.B., F.R.S. Received April 26, 1880. 



(Abstract.) 



The present communication carries forward the subject of mono- 

 trematous generation to a stage beyond those detailed in vols. 124 

 (1834), p. 555, and 155 (1865), p. 671, of the " Philosophical Trans- 

 actions," and relates to the discovery of ova in the right uterus of a 

 female Echidna hystrix, killed 14th September, 1879, and in the left 

 uterus of one killed 30th August, 1879, at Towoomba, Queensland. 

 These, with other specimens, killed between 30th August and 

 10th October, were transmitted to the author by Geo. Fred. Bennett, 

 Esq., Corresponding Member of Zoological Society of London, and 

 were received in February, 1880. 



In the largest ovum the first fission of the germ mass, corresponding 

 to that described by Martin Barry and Bischoff: in the rabbit's ovum, 

 had commenced but was not completed. 



In other respects the ova of Echidna closely correspond with those 

 of the Ornithorhjnchus described and figured in the volume above 

 cited, p. 555, Plate XXV, figs. 3-7. No further progress in embryonal 

 development was detected ; but the fission-stage strengthens the con- 

 clusion, previously arrived at, of the viviparity of the Monotremata. 



The functional equality of both uteri in the genus Echidna corre- 

 sponds with the equal development of the right with left female organs, 

 in which it differs anatomically from the Ornithorhynchus* 



The Society adjourned over the Whitsuntide Recess to Thursday, 

 May 27th. 



2 g 2 



