MISCELLANEA. 455 



development of the ovum are analogous to those perceived in the 

 case of other amphibian ova. The first appearance of the embryo 

 externally takes place from twenty-eight to thirty days after the 

 deposition of the eggs, and is preceded by \iolent movements, which 

 cause the rupture of the shell and liberation of the young animal. 

 When first hatched out, and disengaged from its envelopes, it mea- 

 sures about 0*015 of a millimetre, and the vitellus is at this period re- 

 presented by a small sac the diameter of which is only equal to 0*002 of 

 a millimetre. The hrancTiicB at this stage consist of three very short 

 cylindrical appendages, with a certain number of ramifications, and do 

 not present that extreme division which is characteristic of the adult 

 condition. The second period of development, which dates from the 

 rupture of the envelope of the ovum, may be said to terminate at 

 the time the posterior limbs make their appearance. This stage has 

 not yet been completely investigated. M. Dumeril cannot state the 

 number of weeks it embraces. In specimens hatched on the 19th of 

 February last, and therefore more than two months old, no traces 

 of posterior limbs had been observed, and the anterior extremi- 

 ties which were developed from behind the branchial appendages 

 before the rupture of the egg membrane, had not increased in length. 

 A single adult specimen of the Siredon is now in the Eish-house 

 of the Zoological Society's Gardens, and well merits the attention of 

 those who have not seen this singular perenni-branchiate form in a 

 living state. 



5. Proposed new Expedition in Seaech of De. Leichaedt. 



Prom our active correspondent Dr. E. Mueller, the distinguished 

 Director of the Botanic Gardens at Melbourne, we hear that great 

 exertions are now being made in that city to get up a new expedi- 

 tion in search of Dr. Leichardt and his party, who are generally 

 supposed to have perished in the interior of Australia some sixteen 

 years ago. Intelligence obtained by Mr. Mclntyre during his recent 

 trans- Australian journey is said to have completely disproved the 

 generally acquiesced-in statements of Leichardt' s fall under the 

 hands of savages near Cooper's Creek ; and it is urged that even 

 after this long lapse of time it is possible that some of his brave 

 band may yet be living. We cordially wish success to the under- 

 taking. Although it is of course most probable that the whole 

 of the party have perished long since, it is very desirable that the 

 question as to their real fate should be definitively set at rest. 



