A, A. Julien on Sponge-Spicules. 383 
Specimens, no 8-spined nodes seem to be present, but my o bser 
vations have been too few to determine the extent of the 
variation. 
The central tube appears to pass uninterruptedly through th e 
nodes, to diminish in breadth towards the extremity of the spic- 
‘ule, and to present an open orifice there, into which the water 
enters when the spicule is immersed. The dimensions of these 
spicules are as follows: 
No. of 
Variation. Mean. Measure . 
ments, 
Length, - ee eed es a ee ck inch | g$z inch 9 
Diameter at middle, - - - lrztou-ssrx inch iss's5 inch 9 
= “end, - + + = ¢  —gglgg ine ? 1 
2: or cen Lt eng ed sudou-zsb00 inch yosuT inch 3 
Ratio of bore to diam. of spicula, 4-+ é 3 
1 
The chemical and physical characteristics of this variety are 
Indies. They may come from species of Hy) \ 
orgonioid corals having 
_ 
an axis of parallel siliceous fibers; but Mr. Verrill states that 
mass of parallel fibers. 
Although the mass of spicules is so light as almost to float, 
nevertheless it rapidly falls to pieces when placed in water. It 
is probable therefore that it has not been thrown up by the sea 
in its present form but is the residue from the decomposition of 
a sponge in the sand. Many sponges have been frequently 
thrown up by heavy ground swells at the locality in which the 
mass was found. The negroes state that similar white masses 
have been observed on the beach of the island of St. Martin, 
School of Mines, Columbia College, New York. June, 1865. 
