The Microscope. 295 



appears at lirst to be merely a swelling or bulging out of the dermal 

 covering. If this is watched attentively for an hour or two, it will 

 be found to develop into a finger- like process with an opening at the 

 end, through which the water and small particles contained in it pass 

 out freely. A little bluing or carmine dropped into the water at this 

 time will make the phenomenon much more interesting. At the 

 same time the pores at the base of the sponge may be seen plainly 

 to imbibe the water though in a much less demonstrative way. 



Very young specimens of sponge may be found in June, July 

 and August, but those of larger and mature growth are most abundant 

 in September, October and November. Sponges are readily detected 

 after a little initiation into the art of collecting, by their whitish- 

 brown or pea-green color and bristly surface. They vary in size 

 from half that of a pea to that of the fist. The shape is also variable, 

 being globular, oval or flat and often conforming very much to that 

 of the objects on which or between which they grow. They seem to 

 prefer darkness, though they are frequently found exposed to con- 

 siderable light. They may be looked for in the margins of rivers, 

 lakes and ponds, and sometimes in deep water. In the last case any 

 convenient drag for reaching the bottom may be used to secure 

 them. I have found them most abundant in slowly-running or still 

 water. The under sides of stones, pieces of wood, and submerged 

 logs or boards often yield a rich supply. The rafts of logs that have 

 been lying a year or two at a mill-dam are sometimes covered with 

 them on the under sides, and I have found it a good plan to make 

 friends with the men who run the logs into the mill, and who, for a 

 small consideration, can be induced to, take the sponges from the logs 

 with a knife and place them evenly on a smooth board to be put 

 away for a day or two until called for. Good specimens are some- 

 times found attached to water-plants in not very shallow water, 

 Anacharis, Utricularia and Myriophillum being their favorites. In 

 some localities the long ribbon-like leaves of the Valisneria spiralis 

 are covered with them. Hundreds of acres of this plant bearing 

 sponges by the pound may be seen in the St. John's River, Florida. 

 The finest specimen of Carterius tubisperma was found on the 

 ground in the Niagara river, where it was partly obscured by weeds. 



Sponges when removed from the places of their growth should 

 be preserved by drying or in alcohol. Every specimen should be 

 labelled as to date and locality. In the search for sponge, as well as 

 most microscopic objects, it is necessary to be provided with a good 

 pocket-lens, and to keep it constantly in use when doubtful or 



