Along the Esseouebo and Potaro. 147 



is more than four inches in length, swordlike and flattened 

 from front to back with serrated edges, the serrations 

 pointing forwards. The wound inflicted by such a wea- 

 pon is formidable in itself ; but recent observations tend 

 to shew that the mucous secretion over them is poison- 

 ous in its nature, and it is this deleterious matter which 

 so often renders the wound serious in its results. 



The two specimens in their colouring and barbs 

 differed considerably from each other and from the 

 specimens met with and described by SCHOMBURGK as 

 separate species ; but it is possible that sexual charac- 

 ters and wide variation may explain these points as 

 found in one species. In the male, which was 

 readily distinguished by clasping organs, the colour 

 was of a dirty, yellowish slate, dotted over with 

 orange spots placed in little groups of from one to six, 

 like the pores in the cyclosystems of the Hydrocorallines ; 

 while the spine was single. In the female, the colour 

 was duller and paler, and the pale orange spots were 

 set in small, nearly black areas, scattered over the body ; 

 while there were two spines, the posterior one beinc 

 shorter. 



The related specimens found and described by 

 SCHOMBURGK, whose figures indicate that the specimens 

 were all females,* were referred to two species : Try-on 

 histrtXy in which the colour is greenish-brown, irregularly 

 spotted over the body with black, and the spine double, 

 the posterior one equal to the anterior ; and the Tryaon 

 garrapa, in which the colour is of a yellow umber-brown, 

 covered with yellowish white spots surrounded with a 

 dark margin, and the spine single. These two apparentlv 



* Fishes of Guiana, Vol. II., Plates 20 and 31. 

 12 



