464 
MR. W. H. CALDWELL ON THE EMBRYOLOGY 
information in Sydney as to where the animals were to be found in sufficient 
numbers for my purpose. On October 12 I started for the colder districts in 
New England, but very soon discovered that no uterine stages were to be obtained 
during that season. I found, however, that the Marsupial Phascolarctos was just 
beginning to breed, and determined accordingly to collect a series of stages. 
W. F. Gordon, Esq., kindly invited me to stay with him at Manar, near Lake 
George, where Phascolarctos is exceedingly numerous. In December I also obtained 
many uterine embryos of Halmaturus rufus, as well as a few of other species. I 
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returned to Sydney early in January, engaged a laboratory assistant, M. Emile 
J toGKT, and soon fitted up as a laboratory rooms given me by the Government in 
Macquarie Street. 
During February and March I made short expeditions in search of Marsupial 
material, and sent home an account of the unique condition of the foetal membranes, 
hitherto overlooked (‘Quart. Journ. Microsc. Sci.,’ vol. 24, 1884). 
Towards the middle of April I went north to the Burnett River to find Ceratodus. 
On the 23rd I obtained males with ripe spermatozoa. Both Ornithorhynchus and 
Echidna seemed to be very numerous in the Burnett district; I decided, therefore, to 
remain there until the Monotreme breeding season was over, in the hope of getting 
both Ceratodus and Monotremes in the same year. The Burnett district presented 
the further advantage of still possessing a considerable number of black natives. 
I afterwards found that without the services of these people I should have had little 
chance of success, and it soon became clear that, in order to work Avith them, I should 
have to live under canvas and carry sufficient provisions for an independent camp. 
As there were still (May) many weeks of winter to pass before Echidna would breed, 
I visited Gayndah, the only inland township on the Burnett River, with the object of 
offering a money reward of £10 to anyone ay ho would sIioav me Ceratodus spawn. 
Soon after, I returned to Dalby to purchase a buggy, horses, and camp outfit, and made 
a flying visit to Sydney to obtain material for a prolonged collecting expedition. 
During part of June and July I spent many hours daily in the water, hunting 
everywhere for the eggs of Ceratodus. Towards the end of July the blacks began to 
collect Echidna, and very soon I had segmenting ova from the uterus. In the second 
week of August I had similar stages in Ornithorhynchus, but it was not until the 
third week that I got the laid eggs from the pouch of Echidna. In the folloAving week 
(August 24) I shot an Ornithorhynchus Avhose first egg had been laid; her second egg 
Avas in a partially dilated os uteri. This egg, of similar appearance to, though slightly 
larger than, that of Echidna, Avas at a stage equal to a 36-hour chick. On the 29th 
I sent in the telegram “Monotremes oviparous, ovum meroblastic” to a neigh¬ 
bouring station, where it would meet the passing mail-man, addressed to my friend 
Professor Liversidge, of the Sydney University, asking him to forward it to the 
British Association at Montreal. Meanwhile I had never relaxed my efforts to find 
Ceratodus; but after four months I Avas beginning to despair of success. Early in 
