ANATOMY OF ACLESIA FREERI. 79 



The liver needs no particular description. It forms a solid, 

 well-defined mass, without division into distinct lobes. The 

 intestine is so closely attached to the liver in most places that 

 it can not be dissected away without rupture. The life-color 

 of the liver is gray with black markings, but after preservation 

 in formalin the liver assumes the usual dark-green color. 



The hepatic ducts form three main ducts, one anterior and 

 two posterior, which open into a short but broad common duct 

 (fig. 21, Plate IV) . The latter receives a few small ducts 

 which are independent of the three larger ducts already men- 

 tioned. The common hepatic duct opens into the stomach by 

 the aperture previously described. 



The right stomatogastric nerve (fig. 21, Plate IV) passes to 

 the dorsal side of the cesophagus, while the left remains ventral. 

 Near the posterior end of the crop these nerves divide into 

 branches which make a ring around the crop and anterior end of 

 the gizzard, and also give off three nerves which pass over 

 the surface of the gizzard, one on the dorsal, one on the ventral, 

 and one on the left side. At the anterior end and near the 

 middle of the stomach these three nerves anastomose in two 

 rings which encircle the stomach. From the second ring, the 

 left and ventral branches proceed to the pylorus, where another 

 ring is formed. From this point, nerves pass along the walls 

 of the intestine, but can not be readily followed. No noticeable 

 enlargements or ganglia occur at the points of anastomosis. 



VASCULAR SYSTEM. 



The auricle (fig. 31, Plate V) is large (23 millimeters wide, 

 9 millimeters long, 7 millimeters deep), its base being expanded 

 so that it covers the base of the gill and extends upon the ante- 

 rior face of the kidney. The reno-pericardial pore is found 

 beneath this part of the auricle. The wall of the auricle is 

 transparent and extremely delicate. Its interior is crossed by 

 numerous anastomosing muscular fibers, which can be seen 

 through the wall. The auricle receives blood through several 

 large openings from the efferent branchial vein, as well as by one 

 or more openings from the kidney. The ventricle (fig. 31, 

 Plate V) is conical (14 millimeters long by 11 millimeters 

 wide) , the base being turned toward the auricle, with thick but 

 spongy walls. The auricle is attached to the ventricle over 

 practically the entire basal surface. The auriculo-ventricular 

 aperture is a wide horizontal slit, 6 millimeters long. Each lip 

 of the slit is turned into the ventricle and forms an efficient 

 semilunar valve, 4 millimeters high (fig. 32, Plate V) . 



