190 HYPOTHALMUS. 



the form to those destitute of teeth, and with the 

 dorsal fin removed from the nape, or placed nearly 

 above the ventral fins, and describes only three spe- 

 cies, one of which is the H. edentatus^ Spix, given 

 under the new title of H. Spixii. He remarks the 

 peculiarity of the branchial arches, and the numer- 

 ous folds and length of intestines confined in a cavity 

 of very limited extent. " The digestive tube com- 

 mences by a long and narrow oesophagus, which is 

 suddenly enlarged to become the stomach, which is 

 short, without forming any pouch ; a contraction 

 marks the pylorus, and immediately commences the 

 duodenum, folded twice upon itself, becomes very 

 narrow, and forms a slender tube, which winds so 

 often that it is impossible to describe the folds. 

 This intestinal mass is embraced by the two trian- 

 gular lobes of the liver, and is concealed by its fatty 

 epiploons. The gall-bladder is small, and there is 

 no swimming-bladder." * 



The characters given by Spix, to Hypothalmus, 

 are as follow :— 



" Denies minutissimi, vix conspicui, velutini. Membrana 

 branchiostega radiis 5 vel 15. Areus branchiales elasmiis in- 

 structi. Os angustum. Cirrhi sex. Caput parvum, ut corpus^ 

 compressum, in rostro depressum et omnino nudum. Oculi in 

 margine inferiori et laterali capitis siti. Pinnae dorsales duse, 

 posterior adiposa. Pinna analis ab ano ad pinnam caudalem 

 producta. Radius primus pinnarum pectoralium et pinnse dor- 

 ealis eseteris paulo validior, serratus." 



* Hist. Nat. des Poissons, xv. p. 22&» 



