J. MURRAY ON WATER-BEARS, OR TARDIGRADA. 18^ 



SYNOPSIS OF THE GENERA AND SPECIES. 



In order to indicate the magnitude of the study which the 

 student has before him when he takes up the Tardigrada, I 

 think it will be well to give a full list of the recognised species, 

 without attempting any diagnosis. 



The list of 120 admitted species is not the result of any very 

 careful weighing of the claims of all the reputed species. It 

 includes all the species which I believe to be good, as well as. 

 many about the validity of which I am very doubtful, but which. 

 I have not been able to study critically. 



I see no object in giving at present any list of synonyms and 

 rejected species. Such a list would be quite formidable in extent 

 and would only trouble beginners in the study, unless accom- 

 panied by critical notes on specific values, which would be outside 

 the scope of this paper. 



Key to the Genera. 



. 8 



. 3 



. 4 



Echiniscus. 



1. With processes (palps or cirri) on the head . 

 Without processes on the head ; rods or nuts in 



pharynx 



2. Back distinctly armour-plated 

 Back not armour-plated 



3. Claws four (in the adult) 

 Claws more than four, usually eight . Echiniscoides. 



4. With processes (setae, palps or spicules) on the 



body ........ 5 



No processes except on the head ... .7 



5. Toes five, bearing spoon-shaped processes, the 



modified claws .... Batillipes. 

 Claws four on each leg . . . . .6 

 Claws one on each leg ... Microlyda. 



6. Head cirri well-developed, short claws borne on 



finger -like processes . . . Halechiniscus, 



Head processes short palps or spicules, claws not 

 on finger-like processes (parasitic) I'etrakentron. 



7. Four similar claws on each foot . . . Oreella. 

 Two slender claws, and two shorter, usually 



branched ..... Mihiesium. 



