Bibliographical Notices. 395 
admits that further observations are required to prove their distinct- 
ness. ‘The characters of the twomamed may be thus expressed :— 
Al. stagnorum, mass gray, polypes with 42-44 tentacula. 
Al. gelatinosa, mass yellowish or gray, polypes with 70 tentacula. 
Of the Plumatella we may confidently assert, that the history and 
figures given by our author are very superior to any hitherto pub- 
lished. His observations go to prove the distinctness of Plumatella 
as a genus, but he has seen only one species, the variations of which 
are not so prominent as to constitute them different in kind: ‘‘ the 
reciprocal resemblance of specimens to each other is not so striking 
as at once to prove identity, though enough to establish kindred.” 
(p. 124.) The tentacula vary apparently from about fifty to seventy, 
and Sir John says that the number certainly augments with age. 
Chapter 7 is devoted to “ Ascidia.”” We must content ourselves 
with a mere indication of the species described. 1. Ascidia villosa 
= Pelonaia corrugata, Forb. 2. As. intestinalis, a species not de- 
scribed by Forbes and Hanley. 3. As. rustica= As. scabra, Forb. 
and Hanl. The “young brood ” of this represented on plate 35 is 
surely a distinct species. 4. As. scabra = As. virginea, Forb. and 
Hanl. 5. As. mentula, a rare and gigantic species. ‘‘ Specimens ob- 
tained in the Orkney Islands are no less than 8 inches in height, 
_ and 3 in their widest diameter.” 6. As. papilla = Cynthia grossu- 
laria, Van Beneden. This is fully described, and its mode of pro- 
pagation ascertained. 
*'The Compound Ascidia”’ are described in Chapter 8, and five 
plates are devoted to their illustration. We cannot undertake to 
collate the species with those described by other authors, for the 
subject is difficult, and specific characters of ready apprehension 
have not been given anywhere. Sir John denominates one kind 
described by him Botryllus verrucosus ; but he has left the others 
figured to be named by those who list. 
Chapter 9 contains good figures of some ‘‘ asteroidal zoophytes,” 
viz. Lobularia digitata, Virgularia mirabilis and Pennatula phosphorea. 
We need scarcely add that the history of each of them is given in 
full and interesting detail. 
The ‘* Actinia”’ or “‘ the Animal Flower”’ is the subject of Chap- 
ter 10, and the portraits of the species are exhibited in five plates. 
After an excellent history of the genus, the author proceeds to de- 
scribe the species whose habits he has studied with so much patience 
and care. 1. Actinia mesembryanthemum. 2. Ac. cerasum= Ae. chio- 
cocca, Johnst. 3. Ac. gemmacea= Ac. coriacea. 4. Ac. elegans, pro- 
bably a new species. 5. Ac. ewplorator = Ac. troglodytes, Johnst. 
6. Ac. lacerata= Ac. anguicoma, Price. 7. Ac. maculata= Adamsia 
palliata. 8. Ac. dianthus. 
Chapter 11 is entitled ‘‘ Miscellaneous Supplementary Observa- 
tions.” It contains some additional remarks on the Hydra tuba, 
the story of whose singular metamorphosis formed such a charming 
episode in the first volume ; and we have also another plate devoted 
to its further illustration. It may be remembered that the Hydra 
tuba, at uncertain epochs of its life, produced in succession, as from 
