392 Bibliographical Notices. 
each after its kind. We have the early stages of one or two species 
distinctly traced; and there is a very good account of their ciliated 
ova. 
The chapter is illustrated with ‘eight plates, representing Flustra 
carbasea, foliacea and truncata. T he Fl. papyracea represented in 
plate 7 is very unlike any specimen of the species we have seen, and 
we are inclined to think it no other than a variety of FY. foliacea. 
Plate 8 represents not solely Flusira Murrayana, but, as we would 
conjecture, three species; viz. fig. 1. Cellularia avicularia; fig. 2. pro- 
bably Flustra Murrayana ; and fig. 6. certainly Flustra avicularis. 
Chapter 2 treats of “‘ Investing Ascidian Zoophytes,’’ and has 
three illustrative plates. ‘The first of them (pl. 9) represents Flustra 
hispida remarkably well; and the species is well described in the 
letter-press. ‘The polype has about thirty-five tentacula. ‘* None 
of the marine ascidian hydra have shown me a complement alike 
numerous. ‘This animal is likewise among the larger species, being 
about a line and a half in height, and the tentacula composing its 
cell expanding nearly as much. Its form is elegant, light and beau- 
tiful. It rises very leisurely and gradually from the cell; but its 
retreat is most precipitate, vanishing in a moment.” (p. 30.) The 
ovum has the same origin and properties as that of Mlusire gene- 
rally, but it is quite different in shape from any of them: it is “* pure 
white, elliptical, thin, and fringed by a border of active cilia,—all 
which renders it a beautiful object under the microscope.” This 
peculiar figure of the ovum, taken in conjunction with the peculiar 
substance of the polypidom, would vindicate the claim of the pro- 
duction to be the type of a new genus. 
Alcyonidium parasiticum (pl. 10) is equally well figured and de- 
scribed. Plate 11 illustrates a new species named Alcyontdium my- 
tili, from its infesting chiefly the shells of the mussel. The species 
would have been better placed appa: ently in the genus Flustra. ‘It 
appears as a small spot, or spreads over a superficial area of various 
extent, until equalling 2 or 3 inches, according to the specimen. The 
diffusing edge is always curvilinear, the patch of dingy white, and sel- 
dom thicker than writing-paper.” ‘‘ ‘Phe upper surface is soft, wholly 
composed of numerous cells, apparently with an elliptical orifice ; 
and the lower or deeper part polyangular. However, the exact form 
of the adult is not to be easily discovered ; and, in general, the real 
figure of the cell seemed to me to be hexagonal.” (p. 86.) We 
- suspect this is the same thing as the Flustra Peachit of Couch. 
The ‘‘ Alcyonium”’ is the subject of Chapter 8. Plates 12, 13, 14 
and 16 illustrate the multiform character of 4. gelatinosum ; plate 15 
is a characteristic figure of 4. hirsutum, here named 4. palmatum; 
and the various figures in plate 17 are referable to the same species. 
Chapter 4 is entitled ‘‘ Miscellaneous Zoophytes.” The first of 
them described is Hydra (Coryna) squamata, pl. 18. figs. 1-10; but 
the species is misnamed, for it is really the Hydractinia echinata. It 
is well described, excepting in so far that the author seems to mistake 
its muricated basis for the epidermis of the shell on which the zoo- 
phyte has grown. The efforts of Sir John to breed the animal were 
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