200 SILURID-E. 



79. ASTEROPHYSUS. 



Asterophysus, Kner, Sitzmiysber. Wien. Acad, xxvii. p. 402. 



A short adipose fin ; dorsal fin short, with a pungent spine and 

 with six (five) soft rays ; anal fin short. Head covered with soft 

 skin above ; barbels six, four of which are at the mandible ; eyes 

 rather small, below the skin. Cleft of the mouth very wide, extend- 

 ing far behind the eye ; teeth in the jaws villiform ; those on the 

 palatines separated by the toothless vomer. The lower jaw promi- 

 nent. The gill-opening does not extend on to the throat. Yentrals 

 ten-rayed, inserted behind the dorsal. 



Brazil. 



1. Asterophysus batrachus. 



Kner, I. c. p. 403. taf. -5. 



B. 4-5. D. 1/5(6?)*. A. 13. lM/7. V. 10. 

 Head as broad as long ; the maxillary barbels extend somewhat 

 behind the head. Dorsal and pectoral spines rather feeble ; caudal 

 forked, with the lobes rounded. Coloration uniform. (Kner.) 

 Marabitanos. 



80. DORAS t. 



Doras, sp., Lacep., Cuv. <§• Vol., Kner. 



Centroehir, Lithodoras, Pterodoras, Platydoras, Acanthodoras, Astro- 

 doras, et Amblydoras, Bleek. Nederl. Tydschr. Dierk. 1863, p. 84. 



Adipose fin short, very distinct ; dorsal with a strong spine and 

 with from five to seven soft rays ; anal short. Teeth villiform, 

 fonning bands in both jaws ; palate edentulous. Cleft of the mouth 

 rather narrow ; barbels six, free, and not fringed. Eyes of mode- 

 rate size. Neck with broad dermal bones ; a large humeral process 

 above the pectoral fin ; a series of shields along the middle of the 

 side of the body and tail, each shield with a compressed, prominent, 

 curved central spine. GiU-openings of moderate width, not ex- 

 tending downwards to the throat. Ventral fins with seven rays, in- 

 serted behind the dorsal. 



Rivers of South America flowing into the Atlantic. 



The species may be divided into two groups : — 



* Lateral shields more than twenty, p. 201. 

 ** Lateral shields less than twenty, p. 20.5. 



* The figure shows sis rays, the description five. 



t 1. Doras crocodili, Humh. Observ. Zool. ii. p. 184. pi. 48. fig. 2. — Centi-ochir 

 crocodili, Aga&s. in Spix, Pise. Bras. p. 14. — Rio Magdalena. 



2. castaneo-ventris, Schonib. Fish. Brit. Guian. p. 16L pi. 3. — River 



Pasawivi. 



3. brunnescens, Schomb. I.e. p. Itjo. Upper Essequibo. 



