228 J. MURRAY ON GASTROTRICHA. 



As there are no type specimens, and only MetchnikofTs descrip- 

 tion to go by, there is no justification for transferring his species 

 to the genus Lepidoderma, as Zelinka does. It is either an 

 Ichthydium Ehr. or insufficiently described and unrecognisable. 



Zelinka's animal may be the one which I here figure. If so 

 it seems to me that the little triangular scales or spines are 

 homologous with the bristles of Chaetonotus, and not with the 

 scales of Lepidoderma, and so it should be placed in the former 

 genus. 



Habitat. Summit of Ben Lawers, Scotland, among moss, 1905. 



Chaetura piscator sp. now (PI. 19, fig. 33). 



Specific characters. Small ; head elongate, egg-shaped, fringed 

 with long setae ; neck moderately constricted ; body spindle- 

 shaped ; each branch of furca forked, branches equal ; trunk 

 bearing at least four longitudinal series of fine bristles shaped like 

 fish-hooks, and some straight setae near the furca. 



General description. Length 150 /x, head 50 /x long by 36 /x 

 wide, trunk 30 fx wide, branches of furca about 12 jx ; hooks 

 project about 15 fx above the surface. 



The head is the widest part of the body. It is fringed by long 

 straight hairs or setae, and bears some larger movable setae which 

 appear to have a tactile function. The neck is slightly constricted, 

 but has a swelling. The dorsal hairs are shaped exactly like fish- 

 hooks, without their barbs. They spring out at nearly right 

 angles to the skin, curve round in the posterior direction, and 

 nearly touch the skin at their tips. I distinguished four rows 

 of them, but in dealing with such excessively fine structures 

 it is not well to state hard-and-fast numbers. Four of the 

 straight setae could be seen dorsally, close by the tail ; the four 

 branches of the furca are nearly equal, slightly curved, and have 

 blunt tips. 



Technically this is a Chaetura, having the branches of the furca 

 furcate, although in MetchnikofTs type species, G. capricornia, 

 they are not properly furcate, but bear little branches on the 

 inner side. As in the type, the head is broader than the trunk 

 and there are stiff bristles over the tail. The fishhook-like setae 

 distinguish it from all other known Gastrotrichs. 



Habitat. Amongst moss, Shetland Islands, 1906. 



