56 ME. W. S. ROWNTREE ON THE 



Alesies macrolepidotus.—AW the lobes very loug, and subequal. Middle lobe the longest. Left lobe 

 the shortest. 



Cit/iarinus.—Jj'iver very small. Three lobes short, triangular, and subequal. 



Distichodus. — Lateral lobes very short, but thick. Middle lobe drawn out as a narrow attenuated 

 ribbon, ending in a small bulbous mass quite in the posterior part of the body-cavity. 



Xenocharax.—lAvev small. Left lobe long and thread-like, extending nearly the length of the body- 

 cavity. Right lobe short, broad, ending bluntly. Middle lobe short. 



Nannocharax. — Left lobe broad, blunt, and longer than stomach. Right lobe short and triangular, and 

 occupying usual position of middle lobe. Middle lobe small, triangular, and displaced to the 

 left. 



Prochilodus. — Right lobe moderately long. Left lobe shorter and thread-like. Middle lobe reduced to 

 a bridge so narrow as not to be definitely traceable across the intervening space. 



Curimatus. — Liver apparently very small. 



The Intestine. 



The intestiue of Characinids is, in the carnivorous forms, including Erytlirinoids, 

 short, simple, and comparatively uniform. Erora the pylorus it first runs backwards, then 

 at a point more or less short of the end of the hody-cavity turns and runs directly forward 

 to about the level of the pyloric cseca, usually to the right of the stomach, and finally 

 proceeds straight back, parallel to its former course, thus forming a single elongated 

 loop. Its walls are iisually thin — in spirit-sjjecimens often fragile — but in Hydrocyon 

 apparently stouter. The terminal portion sometimes appears to be wider than the rest 

 of the coiu'se, but in other cases no difference is perceptible. The appearance naturally 

 depends much on the distension due to contained material. In the specimens of 

 Bryconaethiops examined by me the terminal segment appeared distinctly narrower than 

 the preceding part, which was unusually wide. The length of the intestine, reckoned 

 from the first pyloric appendages, is in these carnivorous forms approximately from two- 

 thirds to four-fifths that of the entire fish, including the tail. In four forms only — 

 Lebiasina, Lepor'mus, Anostomus, and Alestes macrolepidotus — out of the twelve for which 

 I have recorded both measurements has the intestine equalled the fish in length. In 

 the last-named the intestine was longer than the fish in the proportion of about 7 to 5. 

 But this fish appears to be mainly vegetarian. The others were Ilacrodon, Sarcodaces, 

 Hydrocyon, Alestes Kotschyl, Alestes nurse, Ichthyoborus, Tetragonopterus abramis, and 

 Tetragonopterus fasclatus . Very precise measurement of the intestine was often diificult ; 

 and it seems therefore better not to give the exact figures, especially as those obtained 

 from different specimens of the same species were not always in close agreement. All, 

 however, fell within abou.t the limits stated, and foi- a general comparison the 

 measurements were sufiiciently accurate. 



Turning to the herbivorous forms — Citharinoids — very different intestinal conditions 

 from those above described are found to obtain. The intestine is long, sometimes 

 enormously so, and is packed into the form of a flattened spiral, consisting, it may be, of 

 several coils. The following are the measurements which I have thus far been alole to 

 make in this subfamily : — 



