174 



The Rotifera form a very nuiiierous class, the great majority in- 

 habiting fresh water, the number found in salt water being compara- 

 tively small. They are to be found everywhere, in little pools or large 

 bodies of water and by their presence indicate its freedom from the pro- 

 ducts of decomposing matter. The characteristic feature of the little 

 animals is a circle of processes arranged around their head, each one 

 performing a circular motion, the whole giving the appearance of a 

 wheel revolving around the head. 



The marine jelly-fish are re[)resented by two forms. The best 

 known being that many armed minute monster, tlie hydra, wliich, when 

 cut in pieces, grows into as many fully formed individuals. It is very 

 plentiful, and may always be obtained from the muddy bottom of the 

 canal. The other form is more uncommon, its arms are many branched 

 and it remains anchore I to other objects, this species grows as much a 

 two inches in length and in all probability will be found here. 



The fresh water sponges form a sub-order of that extensive class ; 

 some ten genera have been described from all quarters of the globe re- 

 presenting a great many species. They occur in clear water and gi'ow 

 to a considerable size, though the cold of winter always destroys them. 



From these we descend to the single-celled animals, to which the 

 term lafasoriu is properly applied. They are present in all water and 

 TOoisture in countless numbers and furnish a vast field for study ; le- 

 searches in this class has been mostly confined to Europe, the Ameri- 

 can forms have scarcely been worked at all. 



Still lower are the Profo^ca, soft, structureless animals without 

 shape or form, known to you by the amieba. They are innumerable 

 and occur evei-y where. It is a class that has received much attention 

 on this continent, and the recognized autliority is Prof L-eidy's recent 

 work on the Fresh Water Rhizopods of North Ameiica. 



This superficial glance over the vast and varied region, the animal 

 Kingdom, thrown o[)en for us to wander in, is given with the hope that 

 knowing what there is to be done, in learning how many attractive 

 fields there are yet without workers, some otheis may be induced to 

 take a more active interest. Each year should see an addition of new 

 members eager and ambitious to continue tlie work and act as a spur to 

 those alieady engaged. Our first requisite is a complete catalogue of 



