164 w. MILNE ON m-E 



The second segment is much narrower and very short, and seldom 

 much seen. Young specimens have seldom any colour, but can 

 "be identified by the foot. There is no boss on the foot; the 

 elegant dorsal curve of the first segment is quite unbroken, though 

 there is a thickening under the skin, like that described in 

 H. torquata (8). The spurs are short cones often stippled, very 

 diver«^ent, with a straight fairly wide interspace. Occasionally 

 the under border of the spurs may be seen in a straight line 

 with the interspace. The contractile vesicle is large, and flattened 

 posteriorly. 



The egg is large, smooth and oval in shape, equally broad at 

 both ends. 



I have known this animal for many years and have spent more 

 time examining it than any other species. For a long time I was 

 unable to form definite conclusions about some points, and not 

 until it was noticed that there were two species not very unlike in 

 several details. The second one, which turned up occasionally 

 with H. elusa, is paler and more lightly stippled, but for some 

 time I thought that the type varied and included both. 



H. elusa is not sluggish, and when put on a slide creeps about 

 a great deal, and usually takes a long time to settle down to feed. 

 After hours, it may be, one may stop and feed for a short interval 

 and then resume creeping. It may be the second or third day 

 before it begins to feed steadily, and then it does so very quietly, 

 and in a characteristic position. If there be a bit of green moss 

 about, H. elusa is almost certain to take refuge on or below it, 

 and remain there. It is then almost impossible to get it clear. 

 I do not think I have ever noticed it take refuge under withered 

 moss. It feeds very freely on or under the moss, but there, of 

 course, it is not possible to observe it clearly. It is also found 

 feeding quietly in the open. I have often taken notes of one 

 creeping and been unable to see it feeding during the same 

 sitting. Before the next examination the specimen had pro- 

 bably retreated to the moss, or could not be found feeding. Then 

 perhaps what was taken to be but a paler example was found 

 feeding, and a sketch made, which when compared with former 

 sketches usually showed some difference, especially as to upper 

 lip and spurs. I changed my opinion several times with regard 

 to these until I distinguished between the two species. A diffi- 

 culty was, that one or the other was often not to be found when 



