GILBERT AND ST AEKS — FISHES OF PANAMA BAY 



91 



anal ray, and extends beyond the third anal spine a distance less than half the diam- 

 eter of the pupil. The interspinous membrane is not dusky. The dorsal spines are 

 slenderer even than in rohalUo; the third is not heavier than the fourth, and is usually 

 shortened a little, giving a rounded contour to the fin, which is sometimes, however, 

 sharply angular. The second dorsal spine is very short, varying from one-fourth to 

 one-sixth the length of the third. The distance from the vent to the base of the 

 first anal spine equals that between the tip of the snout and some point between the 

 hinder margin of the pupil and the hinder margin of the orbit. The preorbital and 

 the horizontal and vertical limbs of the preopercle are very weakly spinous, the 

 spines being scarcely perceptible in some specimens. There are 2 stronger spines, 

 as usual, at the preopercular angle. The ridges on top of head are low and nar- 

 row; the median pair are most widely separated at a point over the middle of the 

 occiput. There are 5 or 6 developed gill-rakers on the vertical limb of the outer 

 arch, 11 or 12 on the horizontal limb, besides 2 or 3 rudiments on each. There are 

 47 or 48 scales in the lateral line in advance of the base of the caudal, and 74^ in a 

 vertical series between the middle of the soft dorsal and the lateral line. The lateral 

 line is uniformly pale. 



Measurements in Hundredths of Le7igth without Caudal. 



Length in mm. without projecting lower jaw or caudal 



Head without lower jaw 



Depth 



Eye 



Interorbital (bone only) 



Maxillary 



Third dorsal spine 



Fourth dorsal spine 



Fifth dorsal spine 



Second anal spine 



First anal ray 



Second dorsal ray 



Pectoral 



Ventral 



Caudal 



Caudal peduncle (height) 



Vent from front of anal 



Distance from anal to base of ventral spine 



Longest gill-rakers 



250 



i4i 



