53 



THE POPULAR SCIENCE MONTHLY. 



Fig. 1. 





Htalonema Ltjsitanicum, the Glass-rope Sponge. Half the natural size. The brush-like 

 threads at the bottom form a twisted rope terminating in the teat-like projection at the top, 

 where it is covered with fine sponge. This coil is the Glass-Rope. The sheath, or incrus- 

 tation of little starry warts, is the work of a polyp, known as the Palythoa fatua. The 

 conical head is a mass of sponge once called Uarleria. 



