38 Synopsis of the Fresh Water Fishes, 



space is also on the exterior sides, wliicli extends across the 

 greater portion of the width of the base, and thence gradually 

 decreases towards the middle of the spine ; the internal border 

 is serrated for the third or half of its length, commencing at the 

 base ; the length of each spine is generally contained about four 

 times and a half in the extreme length of the fish. The genital 

 papilla is about a third of the length of the ventral fin. 



The female has been described under the name of Callichthys 

 laevigatiis ; in this sex, the spines of the pectorals are for the 

 most part smooth on both sides, but covered on the superior 

 borders with rasp-like asperities as in the male ; the interior 

 borders are strongly serrated for almost the entire length; 

 these spines are never recurved at their apices, but nearly 

 straight for tlie entire length, or very slightly curved inwards ; 

 they are also generally shorter than those of the males, although 

 the length varies, being sometimes nearly a fifth of the entire 

 length, while in other individuals, as in those described by 

 Yalenciennes, they are contained as much as six times and a 

 half in the extreme length of the body. The genital papilla is 

 much shorter than in the male. 



D. I. 7. A. 8. C. I. 6. 6. I. V. 6. P. I. 8. 



The last rays of both the dorsal and anal fins are double. 



The color of the fish preserved in spirits is a dark olive brown 

 above, and lighter beneath, with the margins of the dorso-late- 

 ral plates also lighter. The naked skin of the abdomen is 

 tinged with purple. 



Yague and comprehensive as this description may appear, 

 there cannot be any doubt that it is only applicable to one 

 species. We have so many specimens, and the passages 

 between the aberrant forms are so well established, that we 

 have finally, without hesitation, referred all of them to one 

 and the same species. We had, indeed, at first believed 

 that those individuals in which the azygous plate between the 

 anterior frontals is absent, and in which there is also a broad 



