1888.] MICEOSCOPICAL JOCTENAL. 75 



So much for the amount of growth from single gemmules. Where, how- 

 ever, they were thickly sown, or germinated in sitti upon the stone, so that 

 the contents of several could mingle and flow together, the resultant sponge 

 was very much larger. The mass, if it may be so called, covered, at its best, 

 nearly one-third the surface of the jar ; while those gemmules remaining 

 upon the stone and amongst the spicules of the old sponge, continued to 

 germinate, to form abundaht sarcode and spicules, and, at least in one place, 

 to throw out a long unsupported branch or finger-like process, that ultimately ■ 

 reached a length of two or three inches. 



Of course it was impossible to bring the higher powers of a compound 

 microscope to bear upon "a sponge growing under such circumstances ; a 

 strong Coddington lens was the best that could be applied to this work : 

 but a very fair share of success was obtained by the device of scattering small 

 squares of mica among the growing gemmules, which, when covered by the 

 3-oung sponge, could be removed to the stage of my instrument, covered with 

 water in a compressorium and examined comparatively at leisure. It was a 

 perpetual cause of astonishment to me to see so large a production of silici- 

 ous spicules from a single gallon of water, in which the chemist would prob- 

 ably have failed to find any such constituent. It is worthy of consideration, 

 however, whether such silica as composed the older spicules may not, at 

 least when under the influence of the growth force of the younger sponges, 

 be to some extent soluble. 



As to processes of gathering — I have already mentioned the advantages 

 obtained by the use of the *■ scraper net ' in relatively deep water and in 

 connection with perpendicular timbers, etc. At depths of two feet or less, 

 great facility of action is gained by wearing high rubber boots and wading 

 after our specimens, to pick from the bottom stones, sticks or pieces of 

 waterlogged timber, under w^hich they may be concealed. Where the water 

 is deeper, of course a boat must be used to approach the floating, submerged 

 or dependent sponge-bearing substances. A large, strong knife, or a paper- 

 hanger's scraper, will be found convenient for hand work at short range. A 

 case containing trays an inch or so in depth is suitable for carrying the 

 smaller specimens ; the larger will of course require vessels of greater size. 

 On reaching home or headquarters it is well to select some specimens of 

 characteristic shapes and containing gemmules, for storage in dilute alcohol, 

 making use of wide-mouthed bottles to avoid crushing them. The rest may 

 be spread upon boards in sheltered situations, in the shade (for the sun 

 bleaches them rapidly), and left to dry, turning them every few hours to pre- 

 vent decomposition. If time is limited or the specimens are large, artificial 

 heat may be necessary ; but, whatever process is used, the drying must be 

 thorough^ or mould will soon cover the sponges with a mycelium, which 

 may be beautiful enough in itself, but is far from agreeable or sightly as a 

 feature of the sponge. Whether they are to be dried or preserved in alcohol, 

 they should be dealt with promptly and on no account left to lie long in the 

 water after being gathered. Preserve from dust in covered boxes. 



For the determination of species a few general directions may suflice, and 

 even these will be soon modified to suit the tastes or the ingenuity of the 

 worker. It is assumed that the investigator has already noted the general 

 appearance of the sponge in hand, its color, size, compactness ; whether 

 simply encrusting, or cushion like, sending out finger-like processes, etc. 

 These indications may help an experienced collector to a guess, but there 

 are very few species that even such a one could name, with any confidence, 

 before he had made and examined microscopic preparations of the same. 



A stand, supporting a dozen or more test tubes, say three-fourths of an 

 inch in diameter by an inch and a quarter in depth ; a dropping bottle con- 



