RECENT PROGRESS IN BIOLOGY.
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great interest Mr. Caldwell's account of what goes on inside these eggs while the young one is growing there; that is to say, an account of the differences and resemblances between the structures which gradually arise in these mammals' eggs and those which are familiar to us as occurring in the case of the common fowl.
With regard to the strange fish, Ceratodus, Mr. Caldwell has been no less successful, after much disappointment and persevering search. He has lately sent home a series of photographs showing groups of the black men and women whom he employed to catch the fish, standing by the river-side and holding each one in his arms a newly captured specimen, while some twenty or thirty more of the fish are heaped on the ground. Four years ago, zoölogists were glad to buy spirit-preserved specimens of this fish in London for twenty pounds apiece. Mr. Caldwell has as yet sent home so few reports of his doings in Australia, that every one will be interested in the following letter written from New South Wales in February last: