86 Miscellaneous. 
sequently « real communication between the intestinal vascular 
apparatus and the supposed aquiferous apparatus. The inner vessel 
is separated from the intestine proper by the singular canal whieh 
I propose to name the intestinal siphon, which, originating from the 
upper extremity of the cesophagus, runs to open into the intestine a 
little before its point of reflexion, and which, aecording to certain 
observations, would seem to be destined for the rapid conveyance of 
sea-water into the second bend of the intestine. Beyond the point 
where this canal opens into the intestine, the ‘vessel which ae- 
companies it widens into a great reservoir, from which issue 
numerous vascular branches passing to the intestine. This reservoir 
is produced a little upon the reflected part of the mesentery; but it 
soon diminishes in volume, and becomes very rapidly resolved into 
a network of capillaries, which may be traced for a considerable 
distance upon the mesentery; the inner vessel therefore is not 
prolonged as a distinct vessel upon the second bend of the intestine. 
All along its course the vessel which has just been described emits 
numerous branches which pass to the intestine and constitute the 
afferent branches of a very rich and elegant capillary network, the 
efferent branches of which pass to a trunk passing along the outer 
margin of the intestine, the external marginal trunk. This trunk 
is continued into the mesenteric plate; we have never seen it 
emitting even the smallest branch passing to the test. We do not 
see what return course could be taken by the blood which might get 
into these branches; and it is evident that the external and internal 
marginal vessels constitute the two principal trunks of an isolated 
intestinal vascular system, completed by the capillary network. 
This circle being thus closed there can be no question of branches 
opening towards the test, unless it be possible to close it again. 
The external marginal vessel is prolonged further upon the second 
bend than the internal vessel; but it also diminishes very rapidly 
and does not reach the anus. I have not been able to follow it to 
the ring of the lantern; the injection is always arrested at the 
origin of the cesophagus. Moreover, if this vessel were prolonged as 
far as the lantern, it would necessarily terminate at the same point 
as the vertical canal, which is not very probable. 
In its festooned course along the first bend this vessel splits so as 
to form a thick, nearly circular trunk, which communicates with it 
by its two ends, one situated close to the stomach, the other close to 
the point of reflexion of the intestine. Six vertical branches, at 
nearly equal distances apart, also make a communication between 
the marginal vessel and this circular vessel, which floats freely in 
the liquid of the general cavity, and enjoys, like the marginal 
vessels, a very marked contractility, although this did not appear to 
be rhythmical. 
The histological investigation of the supposed heart showed that 
this organ was nothing but a true gland, the product of which is 
poured into a tubular cavity situated below the vertical canal 
starting from the madreporic plate. This cavity is prolonged into 
an excretory duct, opening also at the infundibuliform space enclosed 
