NO. 6 MYERS AND WADE: NEW WEST COAST FISHES 165 



C. lactea is a smaller, somewhat more delicate fish than G. rubelliilus. 

 Alive, the coloration of both is practically indentical, milk-white with 

 traces of an incomplete dark, reticulated pattern. Upon fixation in an 

 alcohol-formalin mixture, the colors and patterns of lactea do not at once 

 notably change, but the eye stalks retract. On the other hand, the pattern 

 of rubellulus changes almost immediately, by the appearance of the wide 

 reddish, black edged bars, of which the only previous indications were 

 traces of the dark edges, so indistinct that they appeared as a part of a 

 poorly developed reticulation. Probably the two close relatives of 

 G. rubellulus from the Atlantic that have a similar color and pattern also 

 inhabit white coral sand. These are G. rubrocinctus Longley (1934, 

 p. 257) and G. quadrocinctus Beebe and Hollister (1935, p. 222). The 

 relationships of these three species of Gillellus are close and need 

 elucidation. 



Family Microdesmidae 



This small family of blenniform fishes is known so far only from the 

 coasts of tropical America and Cameroon. Three genera were recognized 

 until recently, Microdesrrius, Cerdale, and Leptocerdale, and the family 

 appears in most ichthyological works under the name Cerdalidae. In a 

 recent revision (1936), Reid has placed all the known species in a single 

 genus, Alicrodesmus, of which the other two genera become synonyms. 

 With the disappearance of the name Cerdale, the family name becomes 

 Microdesmidae. 



Reid has based his primary division of the species of Microdesmus on 

 the position of the anus, which, in the known species, is placed either 

 before or after the mid-point of the standard length. In our new species, 

 and, indeed, in some of the others, the vent is so close to this mid-point 

 that the value of the feature as a primary classificatory one becomes 

 questionable. It seems possible that the restricted gill-openings of ionthas 

 (the genotype of Cerdale) and floridanus may be of more importance in a 

 phylogenetic system. If this be true, some authors may prefer to retain 

 these two species in a separate genus, Cerdale, in which case the family 

 name should revert to Cerdalidae. 



Microdesmus reidi, new species 

 Plate 22, figs. 5, 6 



Holotype. — AHF no. 916. 



Type locality. — Station 784-38, Darwin Bay, Tower Island, 

 Galapagos, poisoned with derris root in tide pool, January 17, 1938, by 

 G. S. Myers. 



