14. PTERAGOGUS. 101 



self that Lahnts aper is identical with the fish described by Jenyns. 

 The latter very careful ichthyologist had only a dried skin for ex- 

 amination, owing to which the form of the fish has been represented 

 much too elongate : the posterior canine tooth appears to have been 

 lost in that specimen. 



13. DECODON. 



Cossyphus, sp., Poei/. 



Body moderately compressed, oblong, covered with large scales. 

 Head longer than high ; cheeks, opercles, and lower limb of the 

 praeoperculum scaly, only the posterior limb being naked ; base of 

 the vertical fins not scaly ; lateral line continuous. Teeth in the 

 jaws in a single series ; four canines in each jaw anteriorly ; a pos- 

 terior canine tooth. Formula of the fins : D. i^. A. ^. 

 Caribbean Sea. 



1. Decodon puellaxis. 

 Cossyphus puellaris, Poei/, 3Icm. Cub. ii. p. 210. 



D. ii. A. ^. L. lat. 30. L. transv. |. 



Eye rather large, as wide as the interorbital space, but somewhat 

 shorter than the snout. The height of the body is two-ninths of the 

 total length. Posterior edge of the praeoperculum minutely denticu- 

 lated, angle roimded, somewhat projecting beyond the posterior edge. 

 Operculum produced into a membranaceous flap. Ventral fin not 

 prolonged ; dorsal and anal fins not scaly ; caudal emarginate. Rose- 

 coloured, ^vith three large red blotches ; head with several pearl- 

 coloured streaks : a transverse one between the nostiils, two obUque 

 ones running from the orbit towards the suboperculura, and a broad 

 one from the angle of the mouth to the angle of the praeoperculum. 



Caribbean Sea. 



a. Fine specimen. South America (probably Barbadoes). Presented 

 by Sir R. Schomburgk. 



14. PTERAGOGUS. 



Pteragogus, Peters in Wiegin. Arch. 1855, p. 261. 

 Body compressed, oblong, covered with large scales ; imbricate 

 scales on the cheeks and opercles ; praeoperculum serrated on its pos- 

 terior margin. Teeth in the jaws in a single scries ; foiu' canines 

 anteriorly in each jaw ; a posterior canine tooth ? Base of the dorsal 

 fin scaly. Formula of the fins : D. -f--. A, — . 



•' 11-10 10 



Coast of Mozambique. 



1. Pteragogus opercularis. 



Cossj-phus opercularis, Peters in Wicf/m. Arch. 1855, p. 261 (not 

 Guich.). 



D. ii. A. ^. L. lat. 25. L. transv. ^. 

 The U])pcr profile of the head concave above the eyes ; praeoperculum 



