12 BRITISH FRESHWATER RHIZOPODA. 
nucleoles ; contractile vesicle voluminous ; pseudopodia 
broad and short, usually somewhat angular in outline. 
Length up to 300, or 400; nuclei about 10» in 
diameter. 
Habitat.—Damp moss. Rare. 
Iretanp.—Clare Island, Mayo. 
The nuclei may be very numerous, the number, 
according to Penard, sometimes reaching several 
hundreds; the nucleoli are distinct and scattered, 
they may number twenty but are usually about eight 
or ten. 
The plasma usually has few inclusions, the remains 
- of ingested rotifers and a parasitic bacillus have been 
observed ; the contractile vesicle is exceptionally 
large and its diameter may equal one quarter of the 
length of the organism. 
This species and A. fibrillosa Greeff together with 
A. verrucosa Khrenb. (A. terricola Greeff) form a 
group the members of which are often found in moss 
that is hable to desiccation, and it may be to this 
circumstance that the unusually firm outer covering 
with which they are all provided is due. Whether it 
is a true pellicle or only a hardening of the ectoplasm 
has been much discussed, and for a summary of the 
various opinions the reader is referred to Penard,* 
who after weighing the evidence comes to the con- 
clusion that these species possess a true, although very 
fine, pellicle. 
Specimens of Al. verrucosa in a dried state sent 
through the post from Dr. Penard in Geneva to the 
author in America all revived after a few hours in 
fresh water. 
The three species have characteristic nuclei; those 
of A. fibrillosa are spherical and contain a single 
centrally-placed nucleole, whilst A. rerrucosa has a 
single nucleus which is ovoid and contains numerous 
nucleoles. 
* «Faune Rhiz. du Léman,’ pp. 105-121. 
