122 Bibliographical Notices. 
male and female organ in all adult individuals. ‘The products of 
both organs—spermatozoa and eggs—on their becoming detached, 
are intermingled in the peri-intestinal cavity, where probably the 
latter are impregnated. “The testicle is situated at the extremity of 
the stomach, in the place where we observe the ovary in other 
genera : it appears when the polype approaches to maturity, is un- 
equally pitted, and has very much the aspect of the ovary of birds 
when they are not in season. 
The female organ or ovary is formed on the-inner surface of the 
fold of skin that lines the cell, and on one side near the mouth of 
the sac. It is at first a mere tubercle, similar to an abnormal ex- 
crescence, but it grows rapidly, and ova, in different stages of 
development, are soon visible in it. In the young ova the vesicles 
of Wagner and of Purkinje are distinctly seen. In those more ma- 
ture they have disappeared, and we then discover an external vitel- 
line membrane or chorion, and a vitellus underneath. The ovum 
at maturity tears its envelope and falls into the peri-intestinal cavity. 
From this it escapes into the sea by a distinct opening which is 
formed at the base of the tentacula. On its exclusion the surface 
does not appear to be covered with vibratile cilia ; and Van ng woud 
was unsuccessful in tracing its further evolution. 
The increase of the polypidom from the development " pike | is 
next described. Van Beneden first remarks, that although this 
polype is an animal of considerable complexity in its organization, 
yet we here observe that it can be formed without the vesicle of 
Wagner or of Purkinje, whence it is evident that these vesicles are 
not indispensable to the formation of an animal, and they are to be’ 
looked upon only as a means of isolation for the future individual.’ 
Next the author inquires if all the textures of these inferior entities’ 
proceed from cellules, agreeably to the doctrine of Schwann, and 
he answers in the affirmative, although it is admitted that there are 
differences between the cellules in them and in those of the superior 
animals. After this, Van Beneden proceeds to trace the growth of 
the bud, and the successive evolution of the organs of the polyps’ 
which is done in a very clear and masterly manner. 
The characters of the genus and of its species are next given. 
The Z. repens is exceedingly abundant and common at Ostend. 
The Laguncula elongata, a new species, is of less frequent occurrence: 
it is distinguished by having an elongated pedicle which in general 
exceeds the length of the cell, and the polype has 16 tentacula. 
We reserve the second memoir for a separate notice, for we should 
not like to review in a more cursory manner our author’s much-» 
prized labours. ' There are none on which we set a higher values 
In the meantime we have only to remark, that, in some preliminary" 
observations, Van Beneden expresses his opinion that the Linnean” 
division of the animal kingdom will be found, after all, superior to® 
that of Cuvier or of Blainville, and more in harmony with the deve-' 
lopment of structure. In the first four classes the vitellus is absorbed} 
by the belly: these are the vertebrated animals that may be more” 
appropriately called the Hypovitelliens, or still better the Hypocoty~ 
