FRESH-WATER FISHES OF SIAM, OR THAILAND 537 



Genus VAIMOSA Jordan and Seale 



Vaimosa Jordan and Seale, Bull. U. S. Bur. Fisheries, vol. 25, p. 395, 1906. 

 (Type, Vaimosa fontinalis Jordan and Seale.) 



Under this name is included a large number of Oriental gobies in- 

 habiting fresh-water streams, estuaries, and the shores of islands and 

 coasts. The essential differential features ascribed to the genus are the 

 presence of large scales on the opercle, the absence of scales on the 

 preopercle and cheek, the presence of scales on the top of the head 

 posterior to or between the eyes, and no enlarged teeth in either jaw. 

 The genus is in contrast with Ctenogohius, in which the head is en- 

 tirely naked except for a possible band of scales posterior to the eye, 

 with Gnatholepis in which the opercles and cheek are fully scaled, and 

 with Acentrogohius in which the opercle and preopercle are fully 

 scaled, partly scaled, or naked, and some teeth in both jaws are cani- 

 noid and the posterior teeth in the lower jaw are recurved canines. Re- 

 lations with Stigmatogohius are indicated under that genus. 



The status of Vaimosa^ described from Samoa in 1906, has become 

 unnecessarily involved. Jordan (1920, pt. 4, p. 519) made Vahnosa a 

 synonym oi Mugilogohius of Smitt (1899), following Jordan, Tanaka, 

 and Snyder (1913, p. 345), who indicated Ctenogohius abei Jordan 

 and Snyder as the type of Mugilogohius on the basis of a personal 

 letter written by Smitt in 1903, in which he stated that his type species 

 was the one named Ctenogohius ahei in 1901. 



It is unfortunate that Mugilogohius should ever have been regarded 

 as a valid genus, and nomenclatural propriety will best be served by 

 suppressing it if a proper way can be found. Aside from the fact 

 that no species was named, the genus as defined by Smitt is wholly 

 unrecognizable. Features of cardinal importance in the determina- 

 tion of the genera of gobies, such as dentition, squamation, and fin 

 formulae, are entirely disregarded, and not a single diagnostic char- 

 acter is mentioned. It seems unjustifiable to attempt to validate the 

 genus as of the date of its establishment by accepting as the genotype 

 a species that was undescribed at the time the genus was set up and 

 was first made known two years later. Accepted international rules 

 of zoological nomenclature appear to cover this situation either di- 

 rectly or by implication. Thus, in Opinion No. 46, dealing with the 

 status of genera for which no species was named in the original publi- 

 cation, it was held that no species is available as genotype unless it 

 can be recognized from the original generic description. Such recog- 

 nition being quite impossible in this case, it would seem that this genus 

 must, for this and other obvious reasons, have a very tenuous stand- 

 ing. 



If, however, Mugilogohius can be accorded a degree of validity, it 

 is the opinion of the present writer that the validity should date fi'om 

 the first published correlation of the name with a genotype, in 1913. 



