MARINE DIATOMS OF THE PHILIPPINE ISLANDS 9 



NOMENCLATURE 



The nomenclature used in this report is that which has received 

 the general approval of leading diatomists throughout the world. 

 It involves the rejection of a few names, chiefly generic names, which 

 appear earlier in print, but with verbal description or illustration — 

 or in some cases both — so meager and unsatisfactory as to make it a 

 safer plan to treat them as nomina nuda than to accept the alterna- 

 tive, to so amend and amplify them that they will be distinctively- 

 marked off from other genera subsequently discovered. They com- 

 prise chiefly the following: Hemiptychus for the universally used 

 Arachnoidiscus, Tripodiscus for Aulacodiscus, SpMnctocystis for Cyma- 

 topleura, Cystopleura for Epithemia, Gyrosigma for Pleurosigma, and 

 Tessella for Rliabdonema. These practically defunct genera were 

 admitted into my Diatoms of the Albatross Voyages, but with misgiv- 

 ings as to the necessity and wisdom of the change, a statement to that 

 effect being made in the introduction. I am glad to here note that 

 this upsetting of classical and long established names on my part has 

 not had the slightest influence on subsequent diatom literature. 



While holding to the rigid enforcement of the law of priority in 

 nomenclature in present and future cases, I wish to. call attention 

 to the exceptionally disastrous result of its retroactive enforcement 

 in diatom nomenclature. Many of the names above recorded have 

 been in extensive use for a half century or more in scientific literature, 

 outside of technical diatom publications, as well as in popular litera- 

 ture, because of the uses of diatoms as test objects to determine the 

 excellence of optical instruments, together with other uses. Thus 

 Pleurosigma angulatwn is known to every microscopist or user of 

 optical instruments, and has long been an integral part of literature 

 bearing on applied optics. But nobody has hoard of Gyrosigma 

 thuringicum , a name applied to the same diatom at a slightly earlier 

 date. And what intensifies the difficulty of justifying such drastic 

 retroactive enforcement of a new rule here is that the great works of 

 diatom taxonomy are rare and so expensive to produce that there is 

 little, if any, chance of new editions ever being published. The iden- 

 tification of ninety-nine hundredths of the 7,000 or more species of 

 diatoms must always be done by means of thesa classical illustrated 

 publications, as, for example, the works of William Smith, Ehrenberg, 

 Greville, Gregory, Grunow, Schmidt, De Toni, Van Heurck, in all of 

 which these long accepted names are generally used, in preference to 

 the obscure and more or less questionable ones above mentioned. 



After many years of diatom study I have come to repose great 

 confidence in the opinions of the late Dr. Henri Van Heurck, because 

 of his wide knowledge and his spirit of conservatism; and in this 

 matter of the above obscure names his position is the same as that 

 already stated. 



