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XXII. On the Anatomy and the Affinities of the Family of the Medusae. By Thomas 
Henry Huxley, Esq., Assistant-Surgeon of H.M.S. Rattlesnahe, now engaged in 
a Surveying Voyage conducted by Capt. Stanley on the Coasts of Australia and 
New Guinea. Communicated by the Bishop of Norwich, F.R.S. 
Received March 29, — Read June 21, 1849. 
1. Perhaps no class of animals has been so much investigated with so little 
satisfactory and comprehensive result as the family of the Medusce, under which 
name I include here the Medusce, Monostomatae and Rhizostomidce ; and this, not for 
the want of patience or ability on the part of the observers (the names of Ehrenberg, 
Milne -Edwards, and He Blainville, are sufficient guarantees for the excellence of 
their observations), but rather because they have contented themselves with stating 
matters of detail concerning particular genera and species, instead of giving broad 
and general views of the whole class, considered as organized upon a given type, and 
inquiring into its relations with other families. 
2. Tt is my intention to endeavour to supply this want in the present paper — 
with what success the reader must judge. I am fully aware of the difficulty of the 
task, and of my own incompetency to treat it as might be wished ; but, on the other 
hand, I may perhaps plead that in the course of a cruise of some months along the 
east coast of Australia and in Bass’s Strait I have enjoyed peculiar opportunities for 
investigations of this kind, and that the study of other families hitherto but imper- 
fectly known, has done much towards suggesting a clue in unravelling many com- 
plexities, at first sight not very intelligible. 
3. From the time of Peron and Lesueur downwards, much has been said of the 
difficulties attending the examination of the Medusse. I confess I think that they 
have been greatly exaggerated ; at least, with a good microscope and a good light 
(with the ship tolerably steady), I never failed in procuring all the information I re- 
quired. The great matter is to obtain a good successive supply of specimens, as the 
more delicate oceanic species are usually unfit for examination within a few hours 
after they are taken. 
Section I.- — Of the Anatomy of the Medusce. 
4. A fully-developed Medusa has the following parts: — 1. A disc. 2. Tentacles 
and vesicular bodies at the margins of this disc. 3. A stomach and canals pro- 
ceeding from it ; and 4. Generative organs, either ovaria or testes. The tentacula 
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