Alternate generations, in Hydrozoa.
"More Letters of Charles Darwin Volume II" by Charles Darwin
HYDROZOA, nerve-tissue in, 41.
"The Dawn of Reason" by James Weir
In the above-given classification, the Scyphomedusae, formerly included with the Hydromedusae as Hydrozoa, are placed nearer the Anthozoa.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 6" by Various
THE PHYLUM COELENTERATA AND THE CLASS HYDROZOA.
"Freshwater Sponges, Hydroids & Polyzoa" by Nelson Annandale
The Actinozoa (anemonies, &c.) and the Hydrozoa (polyps) constitute the COELENTERA of Frey and Leuckart.
"Marvels of Pond-life" by Henry J. Slack
The Hydromedusae represent, therefore, a sub-class of the Hydrozoa.
"Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 2" by Various