274 



HARDWICKE'S SCIENCE-GOSSIP. 



in retraction ; head long and narrow ; anterior part 

 of trunk distinct. Toes short, rarely separated, 

 somewhat blade-shaped, but obscurely shouldered 

 on outer edge, claw one-third of toe, slightly de- 

 flexed. 



The length of mature specimens is not much less 

 than that of Z>. inermis. but the creature is decidedly 

 narrower, and so delicate in its appearance, that 

 when the alimentary canal is not gorged with food, 

 it can only be distinguished from neighbouring 

 objects by its movements. I have never observed it 

 to swim, but it glides about with much vivacity and 

 many contortions. Indeed, at first sight, I took my 

 earliest specimen to be a Diglena (of the permollis 

 section), and not until I got a J-inch objective to 

 bear upon it, did I recognise that it belonged to the 

 Distylae. In its quickness of movement it almost 

 rivals Stephanops stylatas, in company with which it 

 occurred, and it was no easy matter to distinguish 

 between young specimens of the two species. The 

 shape of the toes and the outline, both in retraction 

 and extended, sufficiently distinguish it from Distyla 

 Hornemanni, while the front, gaping in retraction (so 

 that the outline of the opening is almost a rectangle, 

 scarcely longer than broad) separates it from all other 

 described species, apart from other peculiarities. 



The long head narrows suddenly to a blunt point, 

 overhanging the oblique face. A faint constriction 

 marks off the anterior part of the trunk, and this 

 part is almost entirely occupied by the mastax when 

 in its normal position. The greatest breadth of the 

 body is just behind the centre. The lorica, while 

 generally very membranous, is apparently a shade 

 stiffer towards tbe edges, as I have seen short lateral 

 points when in extreme retraction. There is no 

 trace of markings or folds, and it is impossible to 

 assign any definite outline to the dorsal or ventral 

 plates. I believe that the sulcus is very shallow. 

 The shield-plate over the foot, and the hinge-plate 

 on the ventral surface, seem to be the only shelly 

 portions of the integument. The produced anterior 

 point of the hinge-plate is, I think, peculiar to this 

 species. The mastax is stout and scarcely so 

 elongate as usual. The brain is long and apparently 

 simple, and a minute red eye can just be defined. 

 Between the mastax and the stomach is usually a 

 clear space, crossed only by the oesophagus, which 

 is rather long, and exhibits the customary rhythmical 

 undulating movement. The stomach, intestine, gastric 

 and foot glands seem normal. 



The toes in the living specimens watched, were 

 never observed to be voluntarily separated for the 

 briefest period, and I only saw them slightly apart in 

 a specimen accidentally crushed. They were then 

 seen to be somewhat blade-shaped, somewhat rod- 

 shaped, and in lateral view slightly decurved. 



Numerous specimens occurred among sphagnum 

 gathered in February, 189 1, in Epping Forest. 

 Length, about ^j^th inch ; toes about Trg^th inch. 



Distyla inermis, n. sp. 



Sp. Oh. — Small, but of elongate form ; lorica 

 membranous throughout, anterior margins appressed 

 in retraction. Head long and tapering ; anterior 

 part of trunk distinct ; toes short, somewhat blade- 

 shaped, but obscurely shouldered on outer edge ; 

 claw one-third of toe, tips very slightly reflexed. 



The points selected for the above technical de- 

 scription of this species correspond, with but three 

 exceptions, to those assigned to D. agilis, and the 

 figures given of the appearance in dorsal view of the 

 two forms, may be thought to indicate that they are but 

 varieties of one species. In their elongate outline, in 

 the shortness of the toes, and the comparative softness 

 of that covering which scarcely merits the name lorica, 

 they are certainly near to each other, and distinct from 

 their congeners. It is only necessary to define more 

 particularly the characters by which D. inermis 

 may be unfailingly distinguished from D. agilis. 

 It is a shade longer and decidedly more robust ; the 

 face is almost prone, not oblique ; and the tapering 

 head is rounded in front, not pointed. The toes, 

 though short for a Distyla, are proportionately 

 longer, and usually, but not invariably, appressed, 

 and the claw-tips have just begun to turn upwards. 

 The shield-plate above the foot is less square. The 

 lines marking the lateral edges of the hinge-plate, 

 are slightly curved inwards anteriorly, and in one 

 case, indeed, appeared to me actually to meet, yet 

 there was no produced point as in D. agilis. The 

 lateral infold was very shallow, and although mode- 

 rately broad, could only be defined in side view and in 

 a favourable position. The tapering claws are flexible, 

 bending from their bases or from points nearer to 

 their tips, according 'to pressure applied. 



Specimens kept in captivity laid eggs freely, attach- 

 ing them simply to the surface of the glass. They 

 appeared to be double-shelled, but hatched out in the 

 course of a few days. The outer shell measured 

 3!^ inch longest diameter, the inner about Jth less. 



In retraction the anterior margins of the lorica are 

 appressed, and there is a definite outline recurring 

 after each muscular contraction. 



The species swims readily enough, but prefers to 

 glide quietly among the floccose sediment, nibbling 

 at the particles of food. While thus feeding, it& 

 contortions are frequent but not violent, and it is 

 most unwilling at any time to completely retract its 

 anterior parts, or to remain retracted, and when it 

 has assumed this position I have never seen any 

 indication of lateral points. 



Plentiful in sphagnum from Sandown (I.W.), and 

 in another moss from one locality in Epping Forest. 

 Length, total T J Tr inch, toes only xtsu m ch> or about 

 one-seventh of the whole. 



Monostyla bifurca, n. sp. 

 Sp. Ch. — Elongate, free from wrinkles. Lorica 

 membranous ; in retraction anterior margins slightly 



