224 J. MURRAY ON GASTROTRICHA. 



diagnoses at their face value, it appears that several of these 

 species differ from any of those described in the works known 

 to me. 



I would have dealt with these in the usual way and described 

 them as new species, but just as I was finishing this paper Mr. 

 Harring of Washington was good enough to call my attention 

 to a paper by Marcolongo which I had overlooked (40). In that 

 paper there are described a number of new species of Chaetonotus, 

 as well as a new family and genus. 



Mr. Harring has kindly transcribed the descriptions, which 

 appear to be better than such things usually are, but as they 

 are unaccompanied by figures no certain identification is possible. 

 I consider all descriptions of animals in this group unaccompanied 

 by figures as insufficient, but we are promised figures in a forth- 

 coming work by the same author. 



In the circumstances I have no alternative but to withdraw 

 my new species in the meantime, but there can be no harm in 

 figuring and describing them as animals I have actually seen. 



Several of these are figured on the plate, in company with 

 others which I do nob suppose to be new species. 



The species of Chaetura I can describe with an easy mind, as 

 no one since Metchnikoff has ever described a species of this 

 genus. 



Ichthydium sp. (PL 19, fig. 23). 



A graceful little animal, with very slender neck, deeply 

 trefoliate head and long furca. The branches of the furca 

 are close together at the base, and diverge, tapering to points. 

 No tactile setae are noted, but the animal probably had them. 

 Length about 130 fx. 



Habitat. Amongst Sphaynum, Fort Augustus, Scotland, 1904. 



It is a good deal like Joblot's " poisson a la tete faite en trefle," 

 which some have identified as /. podura. But what was /. podura 

 like ? Various animals have been figured by authors under that 

 name, stout animals and thin animals, with long, slender furca 

 or with little blunt knobs. Usually they do not appear to have 

 gone back to Miiller, or even to Ehrenberg, to find what podura 

 was like. If they had they would have found it was like various 

 things. Miiller's podura possessed bristles (in some figures), and 



