PARASITIC PROTOZOA FROM CEYLON, 81 
The nucleus is round, and measures about 15 win diameter. It is 
composed of a mass of small chromatin granules surrounded by a 
clear achromatic membrane. It usually lies at the anterior end of 
the animal. 
Inside the body, especially in the posterior region, a number of 
particles of wood can usually be seen. How they are ingested I am 
unable to say, as I have never observed an animal in the act of taking 
them up, nor is a mouth present, as far as I have been able to 
make out. 
In addition to these larger forms just described, I always found 
smaller animals possessing a somewhat different structure. The 
anterior end and arrangement of the flagella was different, and the 
nucleus was situated posteriorly (fig. 2). I think these small forms 
probably represent young stages in the life-history of Gymnonympha, 
but in the absence of any very definite intermediate forms, I must 
leave this an open question for the present. These small forms 
were usually about 30-40 vu, in length. 
No animals in division, or at different stages in the life-cycle, have 
I been able to find. 
(2) Nyctotherus termitis, n. sp. 
I propose this name for the new species of ciliate which I found in 
the termite. Hitherto no Nyctotherus has, I believe, been recorded 
from. white ants. ; 
N. termitis differs but slightly from several other members of the 
genus. It resembles N. ovalis, Leidy, of the common cockroach 
(Stylopyga orientalis) closely in general structure. The body is 
roughly ovoid, with the gullet situated near the middle, and running 
in obliquely with a very slight curvature (see fig. 21). It does 
not extend more than about halfway across the animal. There is a 
well-marked, though narrow, anus, near to which—on the ventral 
side—the single contractile vacuole is situated (see fig. 21). The 
meganucleus is ovoid or slightly horseshoe-shaped, and a micro- 
nucleus can sometimes be seen lying in close contact with it. At 
the level of the meganucleus the body shows a more or less strongly 
marked constriction. Another similar constriction can be seen about 
halfway between this and the extreme anterior end. (Cf. fig. 21.) 
The animal attains a length of 60-70 u., and a maximum breadth 
of rather more than 40 yu. 
It is rather a striking fact that the white ant should harbour a 
Nyctotherus so closely resembling that of the cockroach, when it is 
remembered that the Trichonymphids are also confined to these 
two hosts. 
(3) Spirocheta termitis, n. sp. 
Some of the termites which I examined proved to be heavily infect- 
ed with spirochets. As these have not been previously described— 
so far as I am aware—lI propose the name S. termitis for them. 
M 6(22)10 
