DEEP SEA FAUNA 1313 



about sixty in height. The sponge came up folded 

 together, and had much the appearance of a piece 

 of coarse, grayish-colored blanket. 



Near the mouth of the Strait of Gibraltar a number 

 of species were taken in considerable quantity, be- 

 longing to a group which were at first confused with 

 the Hexactinellida?, on account of their frequently 

 forming a similar and equally beautiful continuous 

 network of silica, so as to assume the same resem- 

 blance to delicate lace when boiled in nitric acid. 

 The Corallio-spongiae differ, however, from the 

 Hexactinellidae in one very fundamental character. 

 While in the latter the spicule is hexradiate, in the 

 former it consists of a shaft with three diverging 

 rays at one end. 



This group of sponges are as yet imperfectly 

 known. They seem to pass into such forms as 

 Geodia and Tethya; and the typical example with 

 which we are most familiar is the genus Dactylo- 

 calyx, represented by the cup-shaped pumice-like 

 masses which are thrown ashore from time to time on 

 the West Indian Islands. 



Twelve species of stony corals were dredged in 

 1869. 



From their considerable size, the length and 

 rigidity of their straggling rays, and their habit of 

 clinging to fixed objects, the Echinodermata are not 

 very readily taken by the dredge, but they fall an 

 easy prey to the "hempen tangles." It is possible that 

 this circumstance may to a certain extent exaggerate 

 their apparent abundance at great depths, but we 

 have direct evidence in the actual numbers which 



