bearded hypostoma. 147 



Hypostoma barbatus, Bearded Hypostoma. — 

 L'Hypostome barbu, Hypostomus barbatus, Ctiv. et 

 Valenc. Histoire Naturelle des Polssons, xv. p. 506. 



Length of our specimen six inches and a quarter, 

 to the lowest ray of the tail. The form is de- 

 pressed, particularly that of the head, and the body 

 is nearly without angles, a slight one appearing 

 opposite the opercular openings, where the last 

 plate of the sides joins the skin of the abdomen. 

 The head is thickly studded over with short spines, 

 shai*p and bending backward w^hen viewed through 

 a glass, yet scarcely giving the appearance of " une 

 barbe mal faite," as indicated by Valenciennes. 

 The inter-opercula are furnished each with seven or 

 eight spines, bending and gTadually decreasing in 

 length forwards, that farthest back standing alone, 

 and nearly half an inch in length. The plates on 

 the body are rounded on their posterior edges, ex- 

 cept the four or five first in a line from the oper- 

 cula, which show a blunt angular outline towards 

 the tail, gradually becoming rounded; they are 

 covered with points which assume the form of lines, 

 each terminated with a sharp spine, which gives a 

 ragged outline to the margin of each plate. The ab- 

 domen is entirely smooth and without plates. The 

 mouth and labial disk are rather large, each angle of 

 the latter furnished with a very minute barbule ; but 

 on each side of the mouth there is also two minute 

 barbules or tentaculi. Rays of the fins all rough, 

 those of the pectoral fin becoming strorjgest tow^ards 

 the tip ; but a series also runs in a continued row 



