ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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muscular layer. In all Nemertines a parenchyme is greatly developed 
and the organs are imbedded in a gelatinous tissue ; in many this tissue 
is, in the region of the mid-gut, divided into dissepiments. In some 
there is a cleft which Salensky has compared to a coelom. Though the 
Turbellaria have no spaces between the body-tissue and gut, there are 
muscular septa which are specially noticeable in the elongated Gunda 
segmentata ; on the other hand the marked metamerism of the dissepi- 
ments of the Nemertinea lead us to the Annelids, and especially to the 
Hirudinea. 
In the digestive apparatus of the Nemertinea there are two regions 
distinguished both histologically and morphologically ; the intestine is 
on the type of that of Annelids, while that of Turbellarians is aproctous. 
The characteristic cavity of the proboscis — or rhynchocoelom — is not to 
be compared with any structure in the Turbellaria. As to the Annelids 
the author suggests that, while in them the organs lie in a coelom, only 
a limited coelom is developed in the Nemertinea in which the proboscis 
and part of the dorsal vessel lie — this is the rhynchocoelom, and the 
free bodies which are to be found in it may be compared with the bodies 
of the perivisceral fluid. The body of the more highly organized 
Nemertinea contains two cavities which one may regard as a coelom, but 
it is not to be supposed that these cavities are of equal value. The cleft 
between parenchyme and intestine appears, from its cellular investment 
which is very similar to that of the genital sacs, to be in all probability 
a schizocoel. The rhynchocoelom, on the other hand, represents the 
remains of the primitive cleavage-cavity. Whether or not either of these 
spaces is the homologue of the coelom of Annelids, embryological 
investigations will have to determine. 
The Nemertinea have, but the Turbellaria have not, a blood- 
vascular system. The similarity of the excretory systems of the two 
groups is undoubted, especially if the ends of the excretory vessels in 
Nemertines are, as in Tetrastemma aquarum dulcium , provided with 
ciliated lobules. At the same time, a comparison with the same system 
in Annelids is not excluded, for we have only to call to mind Lanice 
conchilega where four nephridia on either side are connected by a 
longitudinal canal. 
The nervous system of Nemertines passes, as is well known, through 
a number of stages. On the whole, it exhibits a very large number of 
points of resemblance to that of Annelids, while its points of agreement 
with that of the Turbellaria are much more general ; on the other hand, 
the Nemertine eye may be briefly characterized as a Turbellarian eye. 
The extraordinarily complicated generative apparatus of the Tur- 
bellaria finds no parallel in Nemertines, and we must come to the con- 
clusion that while the latter are derived from forms like the Turbellaria 
they branched off along the Annelid stock and again diverged to take 
up an independent line of their own. 
The author describes a number of new species belonging to Cere- 
bratulus, Eupolia , and other genera, and a new genus of the Enopla ; 
this last, which he calls Prosadenoporus, is distinguished from all four- 
eyed aquatic genera by its large cephalic gland, the confluence of mouth 
and proboscis-orifice, and the complete hermaphroditism of its species. 
