46 



THE SPONGES OF THE WEST-CENTRAL PACIFIC 



Text Figure No. 25. Small portion of fiber from Dendrilla verongiformis, X 182. 



The color in life, both as to ectosome and endosome, was yellow, tinged 

 with green. Upon dying in air or in alcohol, the sponge slowly turns to blue- 

 green and finally to blue-black. Several hours were usually required for 

 the complete alteration. The consistency was remarkably like that of many 

 sponges of the genus Verongia: dense and fleshy, almost like the feeling of 

 meat to the touch. Even when fresh and not hardened in a fixative, such a 

 sponge can be sliced rather thin with a razor. 



The surface of this species is covered with conules 2 mm high and 2 to 

 10 mm apart, the larger distances being much more common. The pores and 

 oscules are both microscopic and so readily closed that the maximum diameter 

 cannot be stated. 



The ectosome is a distinct dermis, 50 /x to 65 fx thick, tough, and easily 

 separated from the underlying endosome. The latter is rather dense yet full 

 of large flagellate chambers, 50 fi by 90 fx to 70 p. by 110 ju. in size, and sack- 

 shaped or eurypyllous. The fibers are relatively inconspicuous in the midst 

 of this flesh. 



The skeleton of this species consists of semi-dendritic fibers of very 

 small size. Their maximum size is only about 100 ll in diameter, and they 

 usually are 40 p or less. Typical of the genus Dendrilla, they arise large at 

 the base ; and, as they branch repeatedly, they become somewhat smaller. Yet 

 they are not truly dendritic, because of the fairly numerous anastomoses 

 between them. These fibers are yellow and very distinctly stratified. Here 

 and there in them are small scattered bits of debris, but so infrequent that 

 they cannot properly be called cored fibers. 



This species is characterized to some extent by the peculiar fibers, even 

 more by the pronouncedly fleshy consistency, and most of all by the distinc- 

 tive color and color change. This metachromic effect has been discussed in 

 connection with several species already described. 



The species name refers to the great resemblance of the flesh of this 

 species to that of the genus Verongia. 



