724 



THE NATURE BOOK 



water at a very rapid rate, and which are 

 most curious and interesting to watch 

 under the low powers of a microscope. 

 So transparent are they, that when 



TWO FREE-SWIMMING ROTIFERS. 



resting for a few moments, so that it is 

 possible to use a higher magnification on 

 the microscope, it is quite easy to discern 

 the whole of their internal anatomy and 

 to watch the process of digestion. 



In collecting the stems and roots of 

 the water-plants while seeking for the 

 Brickmaker Rotifers, we are certain also 

 to find some masses of the beautiful 

 Vorticella, or Bell-animalcules. They are 

 singularly graceful, these frail, minute 

 creatures, with their long, slender, anchor- 

 ing stems, crowned by their cup-hke 

 bodies, the rim of each cup bordered 

 ever-moving hairs. An 

 these Bell-animalcules 

 extraordinary scene of 

 slender stems sway 

 to side, and then sud- 

 denly contract into a graceful spiral, only 

 instantly to shoot forth again to their full 

 length, while the fringe of delicate hairs 

 or cilia which surround the edge of the 

 cup-like body are kept in constant 

 motion, producing vorte.x currents by 

 means of which these interesting creatures 

 capture their prey. 



Of extraordinary interest are the fresh- 

 water representatives of the l:)eautiful 

 Moss Animals [Bryozoa), of the rock- 



pools on the seashore. Of the pond- 

 dwelling Bryozoa the beautiful Cristatella 

 is one of the most remarkable and 

 interesting, distinguished alike for the 

 beauty and number of its tentacular 

 breathing organs, and for its active habits ; 

 it creeps slowly, by means of the flattened 

 under surface of the colony, which forms 

 an oval and contractible disc, over the 

 submerged stones and stems. Lophoptts 

 is another interesting fresh-water Bryo- 

 zoon, each member of the colony bearing 

 a wonderful series of delicate tentacles 

 arranged like a horseshoe or crescent- 

 shaped crown. These beautiful and 

 interesting creatures are well worth seek- 

 ing, and are far more numerous in our 

 ponds and streams than is generally 

 supposed. To quote Dr. Allman, who 

 paid so much attention to these fresh- 

 water forms of the Bryozoa, they " may 

 be sought in the still and running waters 

 of the land, in the broad river and the 

 rushing stream, in the pure, cold mountain 

 lake, and the stagnant waters of the moory 

 fen. In interest they yield not one jot to 

 their brethren of the sea, and ofl'er to the 



with a fringe of 

 active group of 

 presents a most 

 animation. The 

 gently from side 



LOPHOrUS: A FRESH-WATER MOSS ANIMAL. 



naturalist an inexhaustible source of 

 gratification in the beauty of their forms 

 and the wonders of their organisation." 



F. Martin Duncan. 



