264 Miscellaneous. 
the surface of the ventral cavity. No breaking-up of these branches 
into capillaries, or union of them with veins, was to be detected. 
Behind the branchial part, along the intestine, capillaries issue 
from the aorta on both sides without the intervention of arteries ; 
and these spread out reticularly in the connective layer of the 
muscularis mucose, hereafter to be described. Their occurrence was 
detected by Langerhans. ‘The intestinal vein is situated upon the 
same layer ventrally. It consists posteriorly of about five reticularly 
communicating parallel tubes; anteriorly the number is reduced 
until there is only one, which gradually narrows, and finally disap- 
pears at the commencement of the cecum. From behind, as far as 
the region where some three tubes are present, short transverse 
branches, into which the capillaries open, are given off on both sides 
from the margin of the tubular system. Then follows a space with- 
out transverse branches or other openings for the capillaries, until 
finally, before the termination, transverse branches again occur ; 
these receive no capillaries, but probably open freely into the lym- 
phatie space, which has still to be described. The intestinal veins 
and their transverse branches are closely covered with transverse 
muscular fibres. 
Joh. Miller, to whom a portion of these vessels was known, sup- 
posed that there was a vascular connexion of the intestinal veins 
with the vessel that I have called the heart; but nothing of the kind 
can be demonstrated. 
The intestinal canal is formed by an inner and an outer layer. 
The inner layer consists of the intestinal epithelium and a muscu- 
laris composed principally of transverse fibres, which, therefore, 
may very well be regarded as a muscularis mucose. In its funda- 
mental substance this layer contains the capillaries ; and the intes- 
tinal vein is applied to its outer surface. The outer layer consists - 
of the peritoneal epithelium and a muscular layer also composed of 
transverse fibres. At the spot where the intestine passes into the 
branchial region the muscles are particularly thick and partly trans- 
versely striated. Between these two layers, which may also be 
traced in the branchial part, there is a wide space. Its complicated 
structure has been described by Langerhans, and particularly accu- 
rately by Rolph. I can confirm his description, and only add to it 
that from the portion of this space which surrounds the branchial 
artery a branch may be traced along the outer surface of each of 
the cleft branchial rods to the section running above along the 
branchie. But whatever may be the development of this space, in 
adult animals it does not serve, as Rolph supposes, as a body-cavity, 
but as a venous or lymphatic space, which cannot well be separated 
in Amphioxus. It not only bears a great quantity of materials 
which coagulate in chromic acid and alcohol, but it also leads into 
the heart. The heart may be traced for some distance forward from 
the apex of the cecum, where it then opens into the venous space 
running along above the branchie. Besides these largest and long- 
est veins, there are shorter veins, which, on each branchial rod along 
the cecum, enter the heart. These veins of the heart were seen by 
J. Miller, but regarded by him as bands between the cecum and 
the branchiee.—Oberhessischen Gesellsch. fiir Natur- und Heilkunde, 
Giessen, November 14, 1877. 
