536 THE POPULAR SCIENCE MONTHLY. 



envelop of lime, this had a core or axis of silica, and a bark of kera- 

 tose. According to Dr. Gray, the Hyalonerna was really two animals, 

 namely, the polyp, represented by the glass coil, and its horny crust ; 

 and the sponge, represented by the conical spicular mass, which as a 

 new species he named Carteria. 



Prof. Milne-Edwards, in 1857, described the sponge-mass and the 

 glass-rope as but one animal, and " degraded the zoophyte to the 

 rank of an incrusting parasite." 



In 1859 appeared the magnificent work of Dr. Brandt, of St. 

 Petersburg, on the Hyalonerna. Now, the tables are completely 

 turned. The silicious rope, and its warty bark, are declared to be 

 parts of a polyp, and the sponge is announced as the parasite ! " at- 

 taching itself to the polyp, gradually penetrating its silicious axis, 

 and finally killing it." Poor, innocent sponge ! Even at the risk of 

 being unparliamentary, we rise to brand that statement as a libel on 

 the sponge. 



In 1860 appeared the elaborate memoir on the Hyalonerna by 

 Prof. Max Schultze, of Bonn. He describes the glass-coil and the 

 sponge-mass as belonging to one and the same animal structure. The 

 warty crust, or case, he refers to a distinct animal, a polyp to which 

 he gives the name Palythoa fatua. Schultze, however, makes the 

 polyp a " commensal " with the sponge ; that is, they both live at 

 the same table, which means that the sponge, by its ciliary action, 

 has to supply food for both. Schultze's exposition is the generally 

 accepted one. His idea of commensalism, however, the present writer 

 cannot accept. Nor can he accept Milne-Edward's degradation of the 

 zoophyte to a parasite. But want of room will not permit a state- 

 ment here of the reasons of his disbelief. 



The curious fact made clear is that, through all these years of 

 earnest investigation, Hyalonerna was studied upside-down, until 

 Prof. Loven published his ingenious paper (in 1867, we think), in 

 which, by a little stalked pyriform deep-sea sponge, he demonstrated 

 the true position or attitude in life of the Hyalonerna. In 1870 Prof. 

 Joseph Leidy attained the same conviction from a different line of 

 argument. It was pretty much as if one should ask, " Should a house 

 stand on its chimney ? " Says Dr. Leidy : " It has occurred to me that 

 the sponge-mass, in its natural position, was uppermost, and was 

 moored by its glassy cable to the sea-bottom ; this opinion is founded 

 on the circumstance that in sponges generally the large oscules from 

 which flow the currents of effete water are uppermost." In fact, these 

 glassy threads, at their lower extremities, spread out in a spiral manner, 

 much like the spray from a turbine water-wheel, and, thus penetrating 

 the mud, afford a good anchorage. This mooring is greatly helped, 

 too, by the peculiar structure of these long silicious needles. These 

 needles, or glassy threads, are, in the body of the fascicle, or skein, 

 cylindrical, and smooth ; but, toward their extremities, they are 



