VISCERAL ANATOMY OF THE CHAEACINIDJi:. 55 



The Liver. 



The liver in the Characinidse presents much variation in form and size. Usually 

 three lobes are more or less distinct, but in some the middle lobe is not developed except 

 as a mere band embracing the oesophagus ventrally and connecting the right and left 

 lobes In others, again, one of the two lateral lobes may be comparatively little developed ; 

 and in one form at least it is the middle lobe which is develojoed at the expense of the 

 others. These conditions, though apparently specifically fairly constant, I regard as being 

 mere adaptations to the exigencies of space and pressure in the abdominal cavity, and 

 therefore of but slight significance. The gall-bladder, in every instance in which I have 

 been able to identify it, was situated at the extremity of the right lobe, being thus 

 sometimes in quite the ]iosterior region of the body-cavity. Its duct could in some cases 

 be traced along the right lobe to the middle liver, and thence to the duodenum, where it 

 became lost amongst the j)yloric appendages. 



The following are the chief variations I have observed in the form of the liver : — 



Macrodun. — No middle lobe. Lateral lobes subequal and slender, extending to behind pelvic fins. 



Left lobe rather the longer, and somewhat expanded at its extremity. 

 Lebiasina. — All three lobes long and slender, and nearly of equal length. 

 " Sarcodaces. — Lateral lobes slender, subequal, and extending beyond stomach. Middle lobe short and 



conical. Left lobe slightly expanded at its extremity. 

 Hydrocyon. — Lateral lobes wide, ending bluntly, and of equal length, terminating just short of the 



pyloric flexure. Middle lobe rather large, triangular, and extending to near the middle of the 



stomach. 

 Salminus. — Right lobe extends beyond stomach. Left lobe pointed and only half length of right lobe. 



Middle lobe little more then a bridge between the two, but somewhat drawn out to a point at 



its left border. 

 Leporinus. — Liver small. Right lobe slender and rather shorter than stomach. Left lobe rather 



shorter, tapering to a filament. Middle lobe short, triangular, also tapering to a filament. 

 Anostomus. — Liver small. Left lobe two-thirds length of stomach. Right lobe slightly shorter. Middle 



lobe short and triangular. All pointed. 

 Serrasalmo. — Tliree lobes of moderate length. Lateral lobes subequal. ^Middle lobe shorter. 

 Sryconaet/tiojjs. — Body of liver a mere narrow baud, drawn out into three long and very slender lobes. 



Middle lobe very long, extending to end of body-cavity. Right lobe almost thread-like, extending 



beyond stomach. Both slightly expanded at extremity. Left lobe the stoutest and shorter than 



stomach. 

 Ichthyohorus and Neoborus. — Liver very small, consisting mainly of the somewhat thick left lobe which 



ends about the middle of the stomacli. Right lobe pointed, but very short. Middle lobe a narrow 



bridge connecting the two. 

 Eupiat/iichthys. — Lobes short, especially the right, which is broad and obtuse. Others subequal. 

 Phago. — All three lobes short. 

 Tetragonopteriis argentatus. — All three lobes subequal and slightly longer than stomach. Right lobe 



the shortest. 

 Tetragonopteriis fasclatns. — Lateral lobes very long, extending almost to end of l)ody-cavity. 

 Alestes Kotschyi. — Latei-al lobes subequal, about length of stomach and moderately stout. Middle lobe 



about half that length and triangular. 

 Alestes nurse. — Three lobes slender, subequal, and extending slightly beyond stomach. 



SECOND SERIES. — ZOOLOGY, VOL. IX. 9 



