380 Analytical Notices of Books. 
those vessels which proceed from the heart appear, it is said, to possess 
proper coats, the capillary canals in which the blood becomes yenous 
offering no trace of a proper vascular membrane. It may be added that 
the two systems seem, both from the description and figure, to pass 
immediately into each other. 
We may also notice in this place, although properly belonging to 
another subdivision, the paper which follows by the same author, ** Ueber. 
“< die Wais diaphana und Nais diastropha mit dem Nerven-und Blut- 
“© system derselben.”? It forms an interesting addition to the little 
knowledge which we preyiously possessed respecting these minute and 
paradoxical Annelida. Dr. Gruithuisen states that he has never observed 
in the aides any other mode of propagation than that by., subdivision ;. 
and thus confirms the observations made by Trembley and Roesel, and if 
we recollect rightly by . Miller also, that they are capable of artificial 
multiplication by cutting their bodies transversely into distinct portions, 
which had been doubted on the authority of Bosc and others. The 
nervous system is in Nais diaphana (wkich is synonymous with WVais 
vermicularis, Auct.) more developed than the apparently simple structure 
of its other organs would have led us to expect ; in Wais diastropha, a 
new species, itis apparently much less complicated. . The author assures 
us that the effect of this difference is strongly marked in the different 
degrees of sensibility and volition evinced by the two species.. For the 
details of the nervous system, as well as of the vascular, we must refer 
to the paper itself. : 
The Dissertation “‘ Ueber ein eigenthiimliches, den Vervus Swinpiehician 
** analoges, Nervensystem der Eingeweide bei den Insecten,”’ by Dr. 
Johannes Miiller, contains a further development of the analogy between 
the nervus recurrens of insects and the nervus sympatheticus of higher 
animals, .The anatomy of this, which he regards as the proper intestinal 
neryous system of insects, had already been given by the authour from a 
species of Phasma in a previous yolume of these. Transactions. In the 
present it is extended to numerous other Orthoptera, as well as to insects 
of most of.the remaining orders. From these observations Dr, Miiller 
is clearly of opinion that the identity of the nervus recurrens with the 
ganglionic system, as it is called in Vertebrata, is clearly made out, and 
that there can be no doubt of its representing the nervus sympatheticus 
