117 
On the development of the Monotremes and 
Ceratodus. 
By W. H. Catpwett, M.A., Balfour Student in the hei 
and Fellow of Gonville ‘and Caius College, Cambridge 
[The Royal Society of N.S.W., 17 December, 1884.] 
The following mi a is from notes of an extempore explanation by 
Mr. “Caldwell of the specimens and embryological material recently obtained. 
im, and exhibi ts ‘d to the members of the Royal Society of N.S.W. on 
December 17, 1884 
Mr. CALDWELL, in introducing his remarks, described the aps eas 
stances under which he had been led tothe Colonies. It wast 
years since his master, the late Professor Balfour, F.R.S., vigeuad 
to him, when still his pupil, that it might be possible for him to 
England and all over the world made this possibility much easier 
to him (Mr. Caldwell), for whilst he had left his post in Cambridge 
he was still attached by holding the Balfour Studentship. 
he came out, two years ago, he found very great difficulty in 
getting specimens of the platypus or echidna. Whilst every one 
told him it was to be obtained in this river or in that, he conte 
found that the skin-hunter had been before him. ‘The first few 
months of the present et he spent in obtaining soa — 
as kangaroos, opossums, and native bears. A knowled 
early stages of the pene was considered in the Colonies to be 
universal property, and every one considered himself qualified to tell 
him how the kangaroos produced — young. Asa matter of fact, 
of modern morphological work upon the subject had not been 
found. Although no naturalist expected to find the kangaroo 
growing on the teat, no one had found the stages from impreg- 
nation up to birth of the young. This material, however, he had 
present year. He had made a number of expeditions all over 
New South Wales in search of marsupials, and in April of this 
