212 J. MURRAY ON GASTROTRICHA. 



general, biological and systematic works known to me are 

 included, as well as any really important faunistic studies. 

 Every work is given in which new species, or supposed new 

 species, or groups of higher value are described. The systematic 

 student wants these principally. There are omitted all merely 

 popular accounts, all trifling faunistic studies (records usually of 

 doubtful value), all references in textbooks of zoology which 

 contain nothing fresh, pronouncements on systematic position, 

 which are mostly only opinions not backed by personal knowledge 

 of the animals. 



Monographists and close students of distribution will require 

 more than this bibliography contains, but they will be able to 

 get it for themselves. 



It is unfortunate that the Gastrotricha, which include those 

 old familiar friends of the students of pond life Chaetonotas 

 larus and Ichthydium podura have no popular name. Gosse's 

 proposed name of " hairy-backed animalcules " is entirely un- 

 suitable, since some of the genera are not hairy-backed 

 [Ichthydium, Lepidoderma). I confess I am unable to suggest 

 any appropriate name. The name suggested by the scientific 

 term for the whole group, which embodies almost the only 

 character which they all possess, is unsuitable for popular use_ 

 The Gastrotricha are not animals which can be named off- 

 hand. The days when we found Chaetonotus larus and 

 Ichthydium podura, occasionally varied by C. maximus, on all our 

 pond- life excursions are over. There are a host of Chaetonoti 

 which have contributed to the records of 0. larus. These species- 

 are all alike to a casual glance, but are distinguished by minute 

 characters the possession of small branches by certain of the 

 bristles, the form of the minute scales which bear the bristles r 

 etc. Some of these are so delicate that a high power and an 

 oil-immersion lens would be needed for their certain deter- 

 mination. This is impossible to apply to a living and lively 

 Chaetonotus, and as to killing the creature merely in order to 

 find out its name, well a philosophic naturalist might prefer- 

 to remain ignorant. To destroy this marvellous little living 

 gem simply to know how to label it ; is it worth while 1 



Now we students of microscopic life cannot pretend to be 

 squeamish ; we have learned to kill lightly ; every time we clean, 

 a cover-glass we annihilate a world. But when it comes to 



