344 Prof. Owen's Description of the Lepidosiren annectens. 



stomach and right ovarium, chiefly in the anterior undivided part of the ab- 

 dominal cavity, but extending- about half an inch beyond the conunencement 

 of the peritoneal mediastinum : it is convex externally, and concave towards 

 the alimentary canal, measuring two inches three lines in length, and eight 

 lines in width. It is of a light brown colour, having its peritoneal coat speckled 

 with dark brown spots. The gall-bladder* is lodged in a notch on the ante- 

 rior surface of the left margin of the liver; it is sunk in the substance of the 

 liver, with part of its surface exposed. The gall-bladder receives the bile by 

 two cyst-hepatic ducts which enter its cervix, and the secretion is carried to 

 the intestine by a single, short, but moderately wide cystic ductf, which ter- 

 minates close to the pylorus, and by a similar but smaller valvular projection. 

 Most of the veins of the abdominal viscera and of the abdominal parietes 

 contribute to form the vena portce : the hepatic veins are four or five in num- 

 ber, but there is a principal one;}:, which emerges from the anterior part of the 

 liver and forms the vena cava. This great vein, with three other vascular 

 trunks, viz. the aorta, pulmonary artery, and pulmonary vein, penetrate the 

 septum which forms the anterior wall of the abdominal cavity. This septum 

 is formed by the fibrous membrane of the abdomen, which is then continued 

 around the pericardium, to which it is united by a cellular medium : a portion 

 of it is seen reflected in Tab. XXV. fig. 1, d. After dissecting away this fibrous 

 tunic the true pericardium § is brought into view : it is protected by the cora- 

 coid bones, which meet below it : one of these is seen turned back in fig. 3, .f. 

 Tab. XXV. ; and the pericardium is removed on that side so as to expose the 



heart. 



Circulating and Respiratory Systems. 



The heart || consists of a single auricle, a ventricle, and a bulbus arteriosus. 

 The auricle^ is large, and is applied to the dorsal surface of the ventricle, 

 but sends forward two apices or appendages into the interspace between the 

 ventricle and the bulbus arteriosus ; one on the right, the other on the left 

 side. The vena cava** terminates in the right side of the auricle ; it is joined 

 by two superior cavse and by the single large pulmonary vein : this veinff 



* Tab. XXV. fig. 2, g. f lb. fig. 2, h. J lb. i. § Tab. XXV. fig. 1 & 3, e. 



II Tab. XXV. fig. 3, a & 6. f Tab. XXVI. fig. 2, a. ** lb. fig. 2, e. 



it lb. fig. 2,/. 



