S6 Miscellaneous. 



sequently u real communication betwcon the intestinal vascular 

 apparatus and the supposed aquiferous ai)paratui^. The inner vessel 

 is separated I'rom the intestine projier by the sinjruhir canal which 

 I propose to name the inlistinal sij^/ion, which, oripinatiiif? from the 

 upper extremitv of the ocsophasfus, runs to open into the intestine a 

 little before its point of retlexion, and which, according 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 ac- 

 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 mcsenteni' ; 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 verj' 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 oesophagus. Moreover, it" 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, ^ix 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 cxcretorj- duct, opening also at the infundibuliforra space enclosed 



