10 
D. C. Danielssen. 
[No. i . 
a thin layer of circular muscle fibres that appear to be a pro- 
longation of the musculosity of the septa, and unite to a very 
broad layer of connective-tissue. This layer is strongly fibrillous, 
and is furnished with a multitude of connective-tissue corpuscles 
having one or several prolongations, and also with nutritory ducts 
with their epithelium. From this connective-tissue layer, pretty 
long, conical prolongations issue, that in a material degree contri- 
bute to form the folds on the inner wall of the gullet-tube and 
intestinal canal (Pl. I fig, 7 f). On the inner surface of the con- 
nective-tissue and its prolongations there is a strongly developed 
muscular layer formed of transversal and longitudinal fibres, and 
clad with a thick epithelium consisting of relatively broad cy- 
linder cells furnished with rather long ciliæ (Pl. I fig. 7 g). Be- 
tween the cells, oblong unicellular mucous glands are seen, whose 
excrementary ducts open out upon the surface of the epithelium. 
As regards the nervous system, I have not very much tosay; 
however, the little I have to report enables me to state, that in 
Fenja mirabilis the nervous system does not differ materially from 
that of the Actiniæ, first shown by the Brothers Hertwig. Just 
below the oral disc — immediately inside (below) the ectoderm, be- 
tween it and the connective-tissue — a narrow layer is observed, 
which is finely granular, and which upon maceration followed with the 
ectoderm. Besides the minute, round, shining grains (transsected 
nerve-fibrils) there are seen, here and there, ganglial cells con- 
taining a large, almost round, nucleus enclosing the nucleal cor- 
puscle and surrounded by a dark protoplasmic mass (Pl. II fig. 4). 
Alongside these ganglia, with their 3 or 4 prolongations (Pl. II fig. 
4 a), long nerve filaments appear, crossing each other, and which 
appear to issue from oblong ganglial nodules rich in protoplasm 
(Pl II fig. 4 b). It has not been possible to detect any nucleus in 
these nodules, and it is possible that they are only artificial vari- 
cose dilations. 
But not only on the oral disc are these ganglia and nervous 
fibrils observed; they are also found upon several parts of the body, 
even far back upon it, and they show themselves pretty distinctly 
in very thin transverse sections, but most distinctly in macerated 
preparations treated with weak osmic acid. It appears to me, 
with considerable certainty, that there is a rich nervous reticu- 
lation with corresponding ganglia distributed over the whole body, 
and that we ought to find that something like it certainly occurs 
on the gullet-tube and intestinal canal. On the uppermost part of 
