TARDIGRADA 91 



NOMENCLATURE 



The nomenclature of the Tardigrada is in need of revision. The validity of many 

 of the accepted names, generic and specific, may be questioned, and some of them 

 will certainly not hold. Professor Hay (6) has suggested a number of corrections 

 which must be made. He has shown that the water-bears have no right to bear the 

 name Tardigrada, which is preoccupied (for a suborder of Edentata). 



The recognition by the earlier naturalists of species having two, three, and four 

 claws may be explained as arising from different interpretations of the claws of 

 Macrobiotus and Milnesium. Macrobiotun may be said to have two forked claws on 

 each foot, or to have four claws united in pairs, just as you please. It is curious 

 that so many good naturalists have recorded a water-bear with three claws, which 

 nobody finds nowadays. 



Milnesium is commonly supposed to be the same as Schrank's Arctiscon, in which 

 case the earlier name must be used, unless it can be shown to be preoccupied. If 

 Schultze's Macrobiotus hufelandii is accepted as the common water-bear, and the 

 same as Miiller's Acarus ursellus, Miiller's specific name should be used for it. All 

 these points would require a very careful revision of the whole literature of the 

 group, and a comparison of all the early descriptions and figures. 



The revision is so important that it should be made in a work of monographic 

 character, or at any rate should comprehend the whole group. While, therefore, in 

 perfect agreement with Professor Hay as to the necessary changes, I shall in this 

 paper continue to use the familiar names. By this means the present report will be 

 kept in line with a whole series of others dealing with the water-bears of various 

 countries under the name " Tardigrada." This report has been announced in the 

 earlier numbers of this publication under that title. 



When changing the name it is desirable that the change should be final, if that 

 be possible. It would require a careful examination of all writings on the subject 

 prior to 1835 to satisfy ourselves that Perty's name Xenomorphidce (22) [which 

 Professor Hay shows to have precedence of Schultze's Arctiscoida (44) ] is really the 

 earliest applied to the water-bears as a family. 



The name Xenomorphidce is a family name, and the group of the water-bears 

 must be considered as of more than family value. Schultze's name Arctiscoida, 

 although proposed as a family name, might be adopted as an ordinal name for the 

 group, and Xenomorpkida for the only family as yet recognised. 



ON THE VALUE OF SPECIES OF TARDIGRADA. 



In the course of this Expedition a great many diverse forms of Tardigrada were 

 collected or observed. Some of these are described in the following papers as species, 



