An As con Sponge. 



AN ASCON SPONGE 

 (Leucosolenia sfi.}. 



General Anatomy. Specimens of Leucosolenia may be 

 abundantly found along the New England shores, attached 

 to rocks, seaweed, and submerged wood-work near the low- 

 tide mark. The specimens submitted for examination will 

 be found to vary considerably in size and to not infrequently 

 occur in little groups or clusters. * 



Examine the specimens with a hand lens and note the fol- 

 lowing : 



Each sponge body is cylindrical and is attached by one end, 

 the proximal, to some foreign support, while its free end 

 presents a large opening, the " osculum" Press the sponge, 

 and note that its wall is flexible. The larger sponges bear 

 buds or branches. Do the buds or branches have oscula? 

 Do the walls of the sponge become in any way different as 

 they approach the rim of the osculum ? 



Carefully lay open the sponge its entire length, cutting 

 from the osculum to the base. The simple central cavity or 

 cloacal chamber is thus exposed. Does the cloacal cham- 

 ber communicate with the smaller cloacal chambers of the 

 buds? 



Place one half of the sponge where it will quickly dry, and 

 the other half, after washing it for a moment in water, place 

 in alum or borax carmine, where it may remain from one to 



1 Specimens preserved in alcohol are more desirable for laboratory 

 work than the living animals. 



