12. GKRUKS. 341 



strong curvature. The upper surface of the skull is furnished with 

 a very high and strong triangular crest, shai-ply pointed above, and 

 supported by two pairs of sh(jrt and low ridges, one before, the other. 

 The occipital crest bifurcates anteriorly, forming the posterior end of 

 a longitudinal groove, in which the processes of the intermaxillaries 

 move, as in a sheath. The base of the skull is rather compressed. The 

 humeral arch does not exhibit any peculiarity. The pubic bones 

 form a very strong and broad triangular plate, and have the exterior 

 ridges much developed. 



There are ton abdominal and fourteen caudal vertebrct, the length 

 of the former portion of the vertebral column being to that of the 

 caudal as 1 : 1-3. The ribs are moderately strong, and have a longi- 

 tuchnal groove anteriorly and posteriorly ; the first rib is short, bent 

 backwards, and has a short prominence at its outer curvature. The 

 neural spines of the posterior abdominal vertebrae gradually become 

 longer, and are furnished with a flat, transparent posterior ridge. 

 The intern eural spines of the spinous dorsal have a similar ridge 

 anteriorly and posteriorly ; and these ridges are so broad, that they 

 do not leave a free space between them. The interneural belonging 

 to the second dorsal spine is exceedingly strong, and nearly equals 

 the first interhaemal ; it is intercalated between the second and third 

 neural spines. The lirst interhaemal, to which are joined the first 

 and second anal spines, is trihedral, exceedingly strong, and attached 

 to the hajmals of the tenth and eleventh vertebrae ; its length equals 

 that of the second vertebra to the ninth. 



2. Gerres poeti. 



Cuv. ^- Val. vi. p. 468; Bleek. Verh. Bat. Genootsch. xxiii. M(hti(l. p. 11. 

 V. -. A. y. 



The diameter of the eye is 2| in the length of the head. Spines 

 of the fins extremely strong and broad ; the length of the third dorsal 

 spine is 2^ in the depth of the body, and its width is one-ninth of 

 its own length. The second anal spine is rather shorter than the 

 third, and one-third of the depth of the body ; its width is one-fifth 

 of its ovm length. Uniform silvei-y ; dorsal above black-cdgcd. 



Coast of Mahe (entering the rivers) ; Sunda Sea. 



3. Gerres rhombeua. 



Shane, Jamaica, ii. pi. 253. f. 1. 



Gerres brasilianu;', Cue. ^ Val. vi. p. 458. 



rhombeus, Cuv. i$- Val. \n. p. 459. 



D. ^. A.Hf-g. L. lat. 38. L. transv. 6/11. 9/15. 



The height of the body is one-half of the total length (without 

 caudal fin). Praeorbital entire ; prseopcrculum distinctly, interoper- 

 culum finely serrated. The sjiincs moderate ; the second of the dorsal 

 two-thirds the Irngth of the head, in young individuals a.<» long as 



