INTRODUCTION. 31 



such situations. The under-sides of the leaves of 

 water-lilies, the common Potamogeton, and other 

 submerged plants, are likewise prolific of species. But 

 for the finer forms of Hyalospheuia, the Xebelas, 

 Heleoperas, etc., search must be made in Sphagnum- 

 bogs and moorland pools. It is in such places that the 

 rare Haphidiophrys elegans, Ampliitrenm (Ditrema) 

 flavum, and A. Wrightii were discovered by Mr. Archer, 

 in Ireland, and there also the singular Chlamydomyxa 

 and the rarer Heliozoa may be looked for with success. 



In matters of habitat the Rhizopoda, like other 

 creatures, have their preferences. It would be in vain, 

 for example, to look for the beautiful Hyalosphenias, 

 the Nebelas, or the rarer Reticularian species in the 

 deep waters of a pool, or for Pelomyxa amongst 

 Sphagnum. Professor Penard has shown, by his inves- 

 tigations at Geneva, that the deep waters of a lake may 

 contain new and unsuspected forms of life. The 

 Amoebde, Diffl/ugiae, and Arcellas seem indifferent to 

 situation. Some of the rarer kinds may be gathered on 

 dripping sandstone rocks among lowforms of vegetation. 



Bogs, again, harbour the rarer species of the filose 

 protoplasts. They are also the habitats of the naked 

 Reticularians, Biomyxa, Gymnophrys, and Penardia, and 

 also of Cklamydornyxa, which in its resting-state is 

 parasitic on Sphagnum. The moss Dicranella cervicu- 

 lata, which covers with a velvety-green mantle the 

 sides of deep drains on peat-bogs, gives shelter to a 

 great variety of forms, notably the delicate little 

 Pamphagus hyalinus, as well as some of the smaller 

 Euglyphse, Cyphoderia ampulla, Trinema acinus, Assulina 

 seminulum, etc. Nebela bursella is met with in associa- 

 tion with these, but in an ill-developed state usually 

 arising from insufficient moisture in summer. Micro- 

 gromia occurs in colonies, mostly in shallow bog-pools, 

 along with Pompliolyxophrys, Acanthocistis, and Vam- 

 pyrella lateritia, but not invariably so. We have met 

 with it in sluggish streams, in masses of filamentous 

 algae, and in ponds among the foliage of aquatic Ht/pn<i ; 



