542 THE POPULAR SCIENCE MONTHLY. 



of the glass-sponges is the emphatically deep water. There are 

 precious stores of exquisite forms and structures, that have never 

 been seen by any except their Creator. One of these, described in 

 Dr. Thompson's book, which was obtained during the cruise of the 

 Lightning, is named in honor of M. Holten, the Danish governor at 

 Faroe, and Prof. Carpenter hence the appellation Holtenia Carpen- 

 teri. It is about nine inches long, and three and a half inches wide. 

 The body of this glass-sponge is of an oval, or egg-shaped form. At 

 the bottom is a great mass of fine silicious threads, like white hairs, 

 wadded together like a mop. These are its anchoring threads. There 

 is a crater, or oscular opening at top, about three-fourths of an inch 

 wide, around which, on the outside, short threads of silica stand out, 

 not unlike a beard. Thus the upper part of the sponge might be 

 likened to a bird's-nest. Hence the Setubal deep-sea shark-fishers, 

 who sometimes bring them up from great depths with threads of Hya- 

 lonema on their fishing-lines, call them " sea-nests." The spicules are 

 arranged in little stellate groups, the effect being that the entire sur- 

 face of the sponge has an ornamentation of stars. 



We can mention but one more of these singular beings. This is 

 the Rossella velata, Fig. 5. And here we will borrow Dr. Thompson's 

 own words: "On August 30, 1870, Mr. Gwyn Jeffreys dredged in 

 651 fathoms in the Atlantic off the mouth of the strait of Gibraltar an 

 exquisite sponge, resembling Holtenia in its general appearance, but 

 differing from it in the singular and beautiful character of having a 

 delicate outer veil, about a centimetre from the surface of the sponge, 

 formed by the interlacing of the four secondary rays of large five- 

 rayed spicules, which send their long shafts from that point vertically 

 into the sponge-body. The surface of the sponge is formed of a net- 

 work of large five-radiate spicules, arranged very much as in Holtenia 

 but the spicules of the sarcode the small spicules which are embedded 

 in the living sponge-jelly are of totally different form. A single 

 large ' osculum ' opens, as in Holtenia, at the top of the sponge, but 

 instead of forming a cup uniformly lined with a netted membrane, the 

 oscular cavity divides at the bottom into a number of branching pas- 

 sages, as in Pheronema Annce, described by Dr. Leidy. The spicules 

 of the 'beard' are more rigid and thicker than those of Holtenia, 

 and scattered among them are some very large four-barbed grappling- 

 hooks." Such is the capital description of the learned naturalist. To 

 be sure, some old " salt " would be more laconic ; for he doubtless 

 would tell you that it was like a pine-apple, with the crown and its 

 core removed. 



We have tried to make plain what is meant by sponge-flesh, for 

 which the word sarcode is used. It should be understood that this 

 sarcode, which is a semi-fluid substance, is simply held to the mesh- 

 like skeleton and to itself by the interlacing of tiny needles of flint, 

 called spicules, so that the albuminous-like flesh is really felted to- 



