512 CALIFORNIA ACADEMY OF SCIENCES. 



scarcely so above; none of them canine-like. Top of 

 head with very small scales. Cheeks and opercles with 

 rudimentary scales above. Preopercle with a concealed 

 antrose hook below as in Eleotris. Scales on body very 

 small, perfectly smooth, partially imbedded; scales on 

 nape and throat minute. Gill membranes extending a 

 little forward below, so that the branchiostegals are free 

 from the isthmus. 



Insertion of dorsal twice as far from middle of base of 

 caudal as from tip of snout; the fin low, its slender rays 

 slightly filamentous. Soft dorsal low, its last ray highest. 

 Anal similar, beginning under second dorsal ray. Cau- 

 dal long, bluntly pointed behind, with strongly procurrent 

 base above and below, the base above two-fifth length of 

 head formed of fourteen short rays, that below a little 

 shorter, of twelve rays, this procurrent portion forming an 

 angle with the caudal proper where it joins it. Pectoral 

 and ventrals short, the ventrals inserted under pectorals. 



Color olive green, dusky above, paler below, but every- 

 where covered with fine black dots. Both dorsals with 

 the membranes pale, the rays each barred with black. 

 Caudal mesially blackish, all the rays barred or chequered 

 in fine pattern. Pectoral and anal pale, similarly speckled; 

 base of pectoral dusky; ventral finely speckled. 

 . One specimen, 6^ inches long, taken by Mr. James 

 A. Richardson in the harbor of La Paz. 



This species seems to be the type of a distinct genus 

 allied to Eleotris and Erotelis, distinguished from Eleo- 

 tris by its very small cycloid scales, from Erotelis by its 

 concealed preopercular hook, and from both by the pro- 

 current caudal fin. The generic name is from ali'=w, to 

 protect; i>h<;a, tail. 



