GILBERT AND ST AEKS— FISHES OF PANAMA BAY 23 



on the u\:>peY surface of the inner rays with a much thickened fold of the integu- 

 ment, as in G. i^latypogon and 0. eigenmanni. 



The specimens taken agree well with Eigenmann's description of the types, 

 except in the size of the palatine patch of teeth, which is in adults about as large as 

 in O. eigenmanni, and many times the size of the small vomerine patch. It is probably 

 true of this species, as of G.gilherti from Mazatlan (Jordan and Gilbert, 1882 h, p. 47, 

 under ^ra«s assimilis), that the palatine bands vary "considerably in size and some- 

 what in form, the width ranging from ^ diameter of eye to I, being generally larger 

 in adults." Eigenmann's type of O. jordani was an immature specimen. In the 

 smaller of our specimens the palatine patch is much less developed than in the 

 adult, though somewhat larger and more ovate than in Eigenmann's figure. 



In both of the specimens taken the fontanel groove terminates a very short 

 distance in advance of the base of the occipital process, not reaching the base of 

 process as described by Eigenmann. 



The gill-rakers number 5 + 11 and 5-f 12, the most anterior being very minute. 

 If the one at the branchial angle be reckoned with the vertical series instead of 

 the horizontal, as above, one of the specimens will have the formula 6-f 10, as com- 

 pared with Eigenmann's type 6-|-9. 



Comparing the Panama material with the co-types of G. gUherti from Mazatlan, 

 it is impossible to detect any appreciable differences, unless possibly in the color, 

 which is lighter in the Mazatlan specimens. G. gilherti is said to lack the pectoral 

 pore, but in reality possesses a minute round pore, as is evident in the co-types exam- 

 ined. The adult G. jordani from Panama has the pore likewise minute, while the 

 younger example has a considerably larger, slightly elongate opening. The width 

 of the mouth is the same in the Mazatlan and Panama specimens; measured exter- 

 nally, at the posterior labial angle, it equals the distance from the tip of the snout 

 to the hinder margin of the pupil, and is contained 2^ to 2^ times in the length 

 of the head. 



The two would be united without question, were it not that the co-types of 

 G. gilherti (three in number) agree perfectly among themselves and differ from the 

 Panama sj^ecimens of G. jordani in having the occipital plate much wider, more evenly 

 rounded in transverse section, and with a much lower keel. The occipital plate is, 

 in each of these specimens, wider than long by half the width of the basal plate of 

 the dorsal spine. In G. jordani the width of the occipital plate is | or | its length. 

 This plate is also much more sharply keeled and more densely granular. On the 

 basis of these differences the two species are held provisionally distinct. 



In both species the upper lobe of the caudal is longer and more falcate than 

 in related species, reaching far beyond the lower lobe, and contained 3^ to 3| in the 

 length. The head is finely and often sparsely granular, the granular area not con- 

 tinued forward in any of the Panama specimens as far as a line joining posterior 

 margins of orbits. The fontanel groove widens anteriorly, is rather deep, with sharply 

 defined margins, and terminates abruptly, not "merging into the broad, flat, smooth, 

 interorbital area" as is described in the type of G. gilberii. 



