1 92 SILURID^E. 



2. Ageniosus sebse. 



Seba, iii. 29. 8. 



Ageneiosus iuermis, Cm: ^- Val. xv. p. 240. pi. 440 (not Silurus 

 inermis, lil.). 



B. 11. D. 1/6. A. 38. P. 1/15. V. 7. 

 The length of the head is contained thrice and a third in the total 

 (with the caudal). Barbels very thin, extending on to the eye. 

 Dorsal and pectoral spines very slender, not serrated, rather stiff. 

 The pectoral fin terminates at some distance from the ventral*. 

 (Val) 

 Surinam. 



3. Ageniosus brevifilis. 



Ctiv. ^ Val XV. p. 242; Knei; Sitzgsber. Wim. Acad. 1858, xxvi. p. 438. 

 B. 11. D. 1/6. A. 34-36. P. 1/14. V. 7. 

 The length of the head is contained thrice and a third (young) or 

 thrice and two-thirds (adult) in the total (without caudal) ; head 

 covered with soft skin above. Two barbels, belonging to the max- 

 illary, not fringed, hidden in a groove. Dorsal spine very slender, 

 pectoral spine flexible. Caudal fin obliquely truncated. The pectoral 

 extends to the ventral, the ventral to the anal. Fins with brown 

 spots ; in young specimens the body also is brown-spotted. 



Cayenne ; Brazil. 

 a, b-c. Adult, half-grown, and young. River Capin, Para. Pur- 

 chased of Mr. Stevens. 

 d. Adult. 



4. Ageniosus dentatus. 



? Silurus inermis, Block, t. 366. 



? Ageneiosus inermis, Lacep. v. pp. 132, 134. 



Ageneiosus dentatus, Kner, Sitzgsber. Wien. Acad. 1858, xxvi. p. 441. 



D. 1/6. A. 40. P. 1/13. V. 7. 



The length of the head is one-fourth of the total (without caudal); 

 occipital process naked. Two very short barbels, not fringed. Dorsal 

 spine very slender, crenulated in front ; pectoral spine flexible. 

 Caudal fin deeply forked. The pectoral does not extend on to the 

 ventral ; the latter reaches beyond the origin of the anal. Brownish 

 above, whitish on the sides and belly. 



Surinam; Brazil. 



a, b. Adult and half-grown. Para. 



73. TETRANEMATICHTHYS. 



Tetranematichthys, Bleek. Nederl Tydschr. Dierk. 1863, p. 108. 

 Adipose fin very short ; dorsal short, with a pungent spine and six 

 soft rays ; anal long. Teeth villiforni, in bands ; palate edentulous. 



* The adipose fin (accordino; to the figure) is situated above the anterior half 

 of tlie anal fin. 



