GILBERT AND ST ARKS — FISHES OF PANAMA BAY 143 



265. Nexilarius concolor {GUI). 



Abundant along rocky shores. 



This species shows remarkable resemblance to Glyphisodon declivifrons. So 

 far as known, the two do not occupy the same waters, G. declivifrons being known 

 only from the coast of Mexico, N. concolor from Panama. For description of our 

 Panama material, see Jordan and Evermann (1898, p. 1559). 



266. Glyphisodon saxatilis {Linnceus). 



Very abundant everywhere about rocks. 



The sides of body show five well-defined dark bars, as described, but the 

 " sixth faint bar " at base of caudal is usually absent. 



Specimens have been compared with material from the Atlantic, and from 

 the Hawaiian Islands. 



267. Microspathodon dorsalis {Gill). 



Seen abundantly at Acapulco and Panama. At Acapulco, on December 

 20th, numerous small specimens of a very brilliant blue were seen about the rocks of 

 the mole. A larger specimen, 130 mm. long, was obtained. In this, the general 

 color is slaty-black, without blue tinge. The blue on the centers of the scales 

 on trunk has already disappeared, but the pair of larger blue spots on the nape, 

 those above the first, sixth and fifteenth scales of lateral line, and the confluent 

 pair immediately behind last dorsal ray are conspicuous. All the larger scales of 

 occiput and jjostorbital region are marked each by a blue spot, the spots irregular in 

 size and shape. An occasional scale on the nape is similarly marked. There is an 

 oblong blue spot on the eye above the pupil. An interrupted blue line runs from 

 supraorbital rim anteriorly above the nostril, the two lines converging toward the 

 tip of the snout, but not reaching it. A second broader streak runs forward from 

 below eye to the depression separating tip of snout from preorbital. A third short 

 streak runs backward from the angle of the mouth, continued by a series of two or 

 three blue spots on successive scales. A blue bar crosses the inner base of the upper 

 pectoral rays. Outer margin of ventrals blue. Margins of dorsal and anal narrowly 

 blue to or nearly to the tips of the lobes. Upper and lower margins of caudal pale, 

 the edge narrow and light blue in color near the base of the fin, wider and translucent 

 opposite the middle of the lobes. Soft dorsal and anal fins have the post-lobular 

 margins transparent, this edge widest and best marked on last dorsal rays. Pectorals 

 have a wide terminal translucent bar, occupying about one-third of the fin. The 

 lower region has a generally distributed bluish tint in life. 



A larger specimen from Panama, 175 mm. long, is no further advanced toward 

 the mature condition. The color is dark slaty-blue, with broad white margins to the 

 pectorals, and narrower margins to the other fins. The larger sky-blue spots still 

 persist, three above the lateral line, a saddle behind dorsal, and a larger spot on each 



