1883.] 



AND HORTICULTURIST, 



309 



sion of the heavier sihcious particles ; whilst in 

 clear lakes and rapidly flowing streams they plant | 

 themselves boldly upon the upper surface of stones 

 in the full sunlight. 



A further hint as to the bodies of water which 

 favor their growth may be found in the fact that 

 three species, one of them the most peculiar of 

 American forms, were found in a stream a child 

 could step over; five were gathered at one time in 

 the submerged cellar of a burnt mill; while the 

 timber-work of the dams upon some of our largest 

 rivers has furnished rich collections ; so that there 

 is scarcely a situation where water stands or runs, 

 excepting upon the muddy bottoms of shallow 

 streams or mill-ponds, where sponges may not be 

 hopefully sought for and frequently discovered. 



The best season for collecting sponges varies 

 with the different species, but may be generally 

 stated to be from the last of July to the middle or 

 latter part of November, when the spicules and 

 statospheres are likely to be fully matured. They 

 may be preserved in dilute alcohol or dried by a 

 few days' exposure to the air; in which condition 

 (as the personal "application" of the foregoing 

 sermon) the writer would be very happy to receive 

 specimens from all parts of this and other coun- 

 tries. If packed in light boxes, strong enough to 

 prevent crushing, the postage by mail (4th class) 

 will be but one cent per ounce, which the writer wil] 

 gladly repay, with any other reasonable expenses. 

 He will acknowledge their receipt, giving names of 

 known species and full credit to the collectors of 

 all that are novel or interesting. Every gathering 

 should be marked with its habitat, the date of col- 

 lection, and the name and address of the sender_ 



A principal motive for the preparation of this at 

 the present time is found in the desirability of 

 securing as full a representation as may be, of the 

 American forms at least, in a monograph now in 

 course of preparation : — but contributions will 

 always be very acceptable. Address, 



Edward Potts, 

 228 S. Third St., Philadelphia, Pa. 



EDITORIAL NOTES. 



The Study of Sponges. — We take pleasure in 

 reproducing in this number the text and illustra- 

 tive plate of a circular entitled "Fresh-water 

 Sponges," recently issued by Mr. Edward Potts, 

 an active member of the Academy of Natural 

 Sciences of Philadelphia. 



To the enthusiastic student there is probably no 



field of scientific investigation which offers a 

 greater prospect of novelty and interest than the 

 study of the flora and fauna of this country as rep- 

 resented in the microscopic lif^e of its lakes and 

 streams. It is a singular fact that while hundreds 

 of naturalists, amateur and professional, have de- 

 voted years to the collection and study of diatoms, 

 the higher algae, the rhizopods and, as we think 

 them, the far more interesting rotifera, polyzoa, &c., 

 hardly any appear to have observed or collected 

 the class of animals described in this article. And 

 yet, occupying fixed positions as there described, 

 and easily recognized by the naked eye, they are 

 far more readily discovered and collected than 

 most of the above-mentioned objects. Simply dry- 

 ing or bottling them in alcohol preserves them for 

 future study ; the process of preparation for micro- 

 scopic investigation is quickly learned, and the 

 forms of their resultant elements, as hinted at in 

 the accompanying plate, are wonderful in their 

 variety and grotesqueness. 



It is greatly to be hoped that many of our young 

 people whose scientific instincts lead them to the 

 exploration of the ponds and creeks of their re- 

 spective neighborhoods, as well as those who 

 haunt our lakes and rivers through the summer 

 season, for the enjoyment they find in boating and 

 bathing, in fishing and shooting along their shores, 

 may be inspired by this article to assist Mr. Potts 

 in the preparation of his intended monograph by 

 forwarding to him specimens of such sponges as 

 his description may have taught them to recognize 

 and appreciate. The season for collecting is at its 

 best; even now (September ist) the slime-like 

 flesh of some species, already mature, is beginning 

 to decay ; their spicules will soon be scattered by 

 the autumn floods, and a few seed-like state- 

 blasts, the winter eggs of the sponges, will alone 

 remain to show where they once had been. 



Echinocactus Sileri. — Just before leaving 

 home we had a cactus from A. L. Siler, which 

 though with long mammae was evidently an Echi- 

 nocactus, and which we could not identify with 

 any described species. On our return we find Dr. 

 Engelmann has named it E. Sileri. As it bloomed 

 with us the flower was greenish and not very 

 showy, but the plant is very pretty and will be 

 very welcome in collections of half-hardy cacti. 



The Banded Rush. — Mr. Nicholson finds this 

 is not a rush (Juncus) at all, but a member of the 

 Sedge family, Scirpus Tabernaemontani, the green 

 form of which is indigenous to Britain as well as to 

 Japan. The leaves are round and rush-like, and 



