THE SPONGIDA OR PORIFERA. 345 



in a greater degree while observing our H. paiiicea, for we saw not 

 one, but nine ' living fountains vomiting forth ' from the large 

 apertures (or oscida^ as these are technically called) of our sponge, 

 and this kept on for several hours without intermission." 



Our third specimen (Fig. 3, Plate XIV.) is a pear-shaped 

 Sponge, two and a quarter inches in length, one and a half inches 

 across at the broadest part, and a little over an inch thick at the 

 large end. It is of a dull grey hue, firm to the touch, a little worm- 

 eaten in parts, and has grown upon and enveloped tw-o branched 

 pieces of sea-weed (^, h). The weed in this instance is Choiidriis ; 

 the fragment associated with the specimen previously described is 

 Fums. Scattered here and there about the sponge, mostly on the 

 side depicted in the illustration, are variously sized oscula (^, a^ a) 

 the largest being three-tenths of an inch in diameter, not raised on 

 conical or mammae-form projections as in our two previous speci- 

 mens, but level with the surface of the body of the sponge, and 

 looking like holes punched in the latter by a miniature cork-borer. 

 This Sponge is of considerable interest to us, since it is the 

 Halichojtdria encriista7is of Johnston, and the Spongia panicea of 

 Grant. "The Spo?igia panicea^'' wrote Grant in 1825, "presents 

 the strongest current which I have seen. . . Two entire round 

 portions of this sponge were placed together in a glass of sea-water, 

 with their orifices opposite to each other, at the distance of two 

 inches ; they appeared to the naked eye like two living batteries, 

 and soon covered each other with feculent matter. I placed one 

 of them in a shallow vessel, and just covered its surface and 

 highest orifice with water. On strewing some powdered chalk 

 upon the surface of the water, the currents were visible at a great 

 distance, and on placing some small pieces of cork or of dry paper 

 over the apertures, could perceive them moving, by the force of 

 the currents, at the distance of ten feet from the table on which 

 the specimen rested. A portion of soft bread, pressed between 

 the fingers into a globular form, with a diameter larger than that 

 of the orifice, and placed over it, was not moved away in a mass 

 by the stream, but was gradually worn down by the current beating 

 on its sides, and thus propelled to a distance in small flakes. A 

 portion of unburnt black coal, with twice the diameter of the 

 orifice, was instantly rolled off the mouth of this living fountain, 

 in whatever position I attempted to make it rest upon it." 



