GASTEROPODES. : 
OF 
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23 
free. Another ovoidal mass afforded Nautilines, such as fig. 5, and the 
empty shells, fig. 6, the parent also being unknown. 
In general, only a single Nautiline is confined in a single ovum or 
capsule ; but there are examples, as we have seen, of three, four, or five 
being together. The integument is often of that extreme tenuity as to 
be almost invisible, and then the common liberty of the inmates is dis- 
covered chiefly by their interchange of places within their prison. While 
doing so within this limited space, a barrier environing the whole evi- 
dently prevents their escape. Perhaps we are yet unprepared for dis- 
cussing this question, which must necessarily remain in much ambiguity 
amidst such scanty materials. Very little of the spawn of aquatic animals 
is known to naturalists, who can determine but little as the pristine pro- 
duce of different tribes. : 
Pendulous clusters, of which we do not witness the origin, are fre- 
quently found on the Corallines,—the Sertularia falcata or halecina, for 
example, composed of spherules under half a line in diameter. They 
resemble bunches of minute currants, each of which is attached by its 
peculiar pedicle to a certain part. A cluster of this kind is represented 
Plate XLVI. fig. 7. A coating of the finest sand sometimes invests the 
bunches, from which others are entirely free. The sand can be discovered 
only by the microscope. I have not seen any species of the Doris to 
which these clusters might be ascribed. 
The clusters, it will be observed, are composed of spherical capsules. 
either invested by sand, or partially or entirely free of it. On June 11, 
two capsules, partially free, being subjected torthe microscope, exposed 
a number of irregular quiescent corpuscula, reddish in the one, and 
yellow in the other. Each of other two contained at least twenty-five 
corpuscula, also quiescent. Although the skin of the capsules was toler- 
ably free of sand, their form was too obscure to be distinctly defined. 
Three of these four capsules are represented as enlarged, figs. 8, eave 
But in other two, entirely divested of the sandy coating, not fewer 
than twenty were discovered pursuing an active course amidst the liquid 
contents, and the last among them especially interchanging their places 
everywhere with the rest, figs. aS 2s 
