SIREN. 397 



The oesophagus, which is pretty large, passes hack, and is continued 

 into the stomach in the same line. The stomach at the posterior end 

 bends a little to the right, where it terminates in the pylorus. The 

 intestines pass back, making many turns. At the posterior end they 

 become nearly straight, ending in what may be called the colon, or 

 rectum, which is a little larger ; but, at the beginning of this larger 

 part of the intestinal tube, there is no valvular structure, and it runs to 

 the anus in a straight direction 1 . 



In the stomach there was some grass and a good deal of moss that 

 grows on stone near waters ; and in both stomach and intestines were a 

 great many small pebbles, as in birds. 



The pancreas is a small body lying above the duodenum, and is at- 

 tached to the left side of the mesentery. 



The liver is principally one long body, chiefly on the right side of the 

 abdomen ; it is pretty close to the heart at the fore-part, and passes 

 back on the right side of the stomach and intestines. The vena portarum 

 enters the liver : the inferior vena cava passes forward in the sulcus of 

 the liver to the auricle. There are two superior venae cavae, one on 

 each side, coming down from the arms and head to the auricle. At its 

 anterior extremity it would appear to be made up of two lobes ; but 



for 1766, Hunter writes, "What answers to the inferior vena cava passes forwards 

 above, but in a sulcus of the liver, and opens into a bag similar to the pericardium ; " 

 and he appends the following note characteristic of his candid devotion to accuracy 

 of statement : — 



" * This account of the venae cavse opening into the cavity of the pericardium may 

 appear incredible ; and it might be supposed that, in the natural state of the parts, 

 there is a canal of communication going from one cava to the other, which being 

 broken or nipped through in the act of catching or killing the animal, would give 

 the appearance above described. I can only say that the appearances were what 

 have been described in three different subjects which I have dissected ; and in all of 

 them the pericardium was full of coagulated blood. But besides the smallness of 

 the subjects, it may be observed that they had been long preserved in spirits, which 

 made them more unfit for anatomical inquiries. They had been in my possession 

 above seven years." There is no preparation in the Hunterian Collection demon- 

 strative of the structure described in the text. I took the first opportunity of dis- 

 secting a siren, to test Hunter's description of the heart and veins, and was led to 

 the discovery of the two distinct auricles, communicated to the Zoological Society 

 in 1834, and published with figures in the 'Transactions,' vol. i. p. 213. The inferior 

 vena cava terminates at the lower part of a large membranous sinus, which also 

 receives the blood from the two superior cavse by two separate orifices. The common 

 trunk of the pulmonary veins seems also to end in this sinus ; but it merely tra- 

 verses it, and opens into a distinct auricular chamber, which is not separated ex- 

 ternally from the apparently single and capacious fimbriated auricle receiving the 

 vena? cavae. See my Preparation, No. 913 a, following No. 913 in the Hunterian 

 Physiological Series.] 



1 [Hunt. Prep. Phys. Series, No. 444.] 



