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 : — 



" Dentes minutissimi, vix conspicui, velutini. INIembrana 

 branchiostega radiis ,5 vel 15, Arcus brancliiales elasmiis in- 

 strueti. Os angiistum. Cirrhi sex. Caput parvum, ut corpus^ 

 eompressum, in rostro depressum et omnino nudum. Oculi in 

 margine inferiori et lateral! capitis siti. Pinnae dorsales du£3, 

 posterior adiposa. Pinna analis ab ano ad pinnam eaudalem 

 producta. Radius primus pinnarum pectoralium et pimise dor- 

 salis caeteris paulo validior, serratus." 



* Hist. Nat. des Poissous, xv. p. 229. 



