164 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 9 



Teeth in jaws in narrow bands of very small, villi form teeth, teeth absent 

 on vomer and palatines. Opercular fringe of 9 to 11 rays. Membrane 

 of subopercle and interopercle expanded and covering throat and bases of 

 pectoral and ventral fins. Branchiostegal rays 6. Pseudobranchiae 

 present. 



Body color in alcohol light tan; dorsally with six quadrate, dark 

 brown spots lying close to dorsal base. A large, dark brown area on the 

 mid-line of the nape before the dorsal fin. The lower edges of the dark, 

 quadrate spots are united by a narrow, irregular, dark line, strong and 

 sharply defined anteriorly, fading posteriorly, and entirely absent on some 

 specimens. Several irregular, brown spots on side just behind and above 

 pectoral base. Fins lighter than body. Head same color as body, a 

 short thin dark line extending downward and backward from the lower 

 edge of the orbit. Interorbital with a small, brown area between the eyes. 

 In life milk-white, with fine, irregular, blackish marks. 



Comparisons. — Two species of Cokeridia are known, C. crossota, the 

 genotype (see Meek and Hildebrand, 1928, p. 905, pi. 89), and C. 

 fimbriata (Reid, 1935, p. 163, fig. 1). The scales are smaller and there 

 are more scales in a lateral series in Cokeridia lactea than in C. crossota, 

 and lactea has a longer head, snout, and maxillary. There are fewer 

 opercular fimbriae in lactea, the body is deeper, and the anal origin is 

 farther back than in crossota. From Cokeridia fimbriata this species 

 differs in having larger scales, fewer dorsal and anal rays, fewer fimbriae 

 on the opercular fringe, no scales above the arch of the lateral line, and 

 in many different proportions. 



Notes. — This species is named from its milk-white color in life. It 

 inhabits coarse, white, coral sand in shallow waters and tide pools in the 

 Galapagos, and in these places is usually associated with another species 

 of Dactyloscopid, Gillellus rubellulus Kendall and Radcliffe (1912, 

 p. 148, pi. 6, fig. 3). The latter is usually the commoner. In life, these 

 two species are so similar that it takes a sharp eye to distinguish them. 

 The senior author first collected these fishes in the milk-white coral sand 

 of the tide pools at Darwin Bay, while using derris. They were not seen 

 at first, but the derris brought them out of the sand, in which they nor- 

 mally lie with only the tip of the snout, the nostrils, and the eyes pro- 

 truding. It was noticed in the field that several of the individuals, out of 

 some fifteen obtained that day, had stalked eyes, but it was not until the 

 catch was sorted aboard ship in the afternoon, when the field preservative 

 had already shrunk the eyes almost back into the retracted position, that 

 the stalk-eyed fish were seen to be plainly different from the others. 



