118 
Nellie Carter. 
TRACHELOMONAS INCONSTANS, A NEW 
FLAGELLATE 
By Nellie Carter, M.Sc. 
I N May, 1918, a collection was made from a small rain-water 
pool near Longmoor Pool at Sutton Park, Warwickshire, which 
proved on examination to contain, in addition to other Flagellates, 
a species of Trachelomonas which is not like any other previously 
recorded and is presumably a new species. The distinctive feature 
seems to be the presence of a prominent nodule or spiny 
excrescence at the posterior end of the organism. 
Fig. 1. A, B, C, D, E, F and H, cases of various individuals x 510 ; 
G, showing the structure of the case x 810 ; I, living individual x 519. 
The living cell is provided with a case, the shape of which is 
variable within certain limits. In the majority of specimens it is 
egg-shaped, the widest part usually being posterior (Fig. 1, D and 
E), but occasionally anterior (Fig. 1, A and H), although in certain 
individuals it may be more or less oval in shape (Pig. 1, F and G). 
The basal nodule is also capable of considerable variation, its size 
probably depending on the age of the individual. In delicate and 
probably newly-formed cases, the nodule may be entirely wanting 
(Fig. 1, A). As a rule it forms a rather button-like thickening or 
conical outgrowth (Fig. 1, B, D, E and G) and frequently there are 
several delicate spicules projecting from it (Fig. 1, D and E). 
Very often it is in the form of a spike (Fig. 1, C and I), orit may be 
two or more fid (Fig. 1, F and I) whilst in older individuals the 
nodule often becomes very large and irregular in form (Fig. 1, H). 
At the anterior end, the case is prolonged to form a distinct neck 
with a collar-like thickening at its base (Fig. 1, G). 
