CAT-FISHES. 567 



Four species from tropical America. Tlie second genus 

 of this sub-family is Helogencs from the Essequibo. 



IV. SiLURiDiE Proteropter^. — The rayed dorsal fin is 

 ahoays present, short, vnth not more than twelve short rays, 

 and belongs to the abdominal portion of the vertebral column, 

 being placed in advance of the vcntrcds. Tlie adipose fin is always 

 present and well developed, although frequently short. The 

 extent of the anal is much inferior to that of the candcd verte- 

 bral column. Tlie gill-membranes are not confiuent tvith the 

 skin of the isthmus, their posterior margin always remaining 

 free even if they are tmited with each other. Whenever the 

 7iasal barbel is present it belongs to the posterior nostril. 



a. Bagrina. 



Bagrus. — Adipose fin long ; a short dorsal with a pungent 

 spine and nine or ten soft rays ; anal fin short, with less than 

 twenty rays. Barbels eight. The anterior and posterior nostrils 

 are remote from each other, the posterior being provided with a 

 barbel. Teeth on the palate in a continuous band. Eyes with 

 a free orbital margin. Caudal forked ; ventrals six-rayed. 



This genus consists of tw^o species only, common in the 

 Nile, viz. the " Bayad," B. bayad, and B. docmac. Both grow 

 to a large size, exceeding a length of five feet, and are eaten. 

 Chrysichthys and Clarotes are two other Siluroid genera from 

 African rivers, closely allied to Bagrus. Similar Siluroids are 

 common in the East Indies, and have been referred to the 

 following genera : Maerones, Pseudobagrtis, Liocassis, Bagroides, 

 Bagrichthys, Rita, Aerochordonichthys, Akysis. 



h. Amiurina. 



Amiurus. — Adipose fin of moderate length ; a short dorsal 

 with a pungent spine and six soft rays ; anal fin of moderate 

 length. Barbels eight. The anterior and posterior nostrils are 

 remote from each other, the posterior being provided with a bar- 



