THE SPONGES OF THE WEST-CENTRAL PACIFIC 57 



Halidona ligidata (Whitelegge) de Laubenfels 



Text Figure No. 32 



This species is here represented by the following : 

 U.S.N.M. No. 23144, My No. M. 528, collected September 20, 1949, by 

 diver in northwestern Guam, northeast of Agana, at Dungas Beach. The 

 depth was less than 2 mm, the substratum dead coral, or shells. The 

 species was common in this one locality. 



The shape is lobate, the lobes about 1 cm in diameter and from 1 mm to 

 6 cm high. A common measurement is 1 by 1 by 3 cm. The total diameter of 

 the sponge is often as much as 14 to 18 cm. The total vertical measurement 

 is often as much as 8 or 10 cm. 



The color varied in life from dull violet to violet-gray. Deeper buried 

 portions might be drab, probably being moribund. The consistency was 

 spongy. 



When out of water, the surface appears punctiform, because the flesh 

 sinks in at the skeletal pores. These are 200 fx or 300 /x in diameter and 

 separated from each other only by fibers which are about 20 /x to 60 /x in 

 diameter. Each such skeletal pore is filled with a thin protoplasmic structure, 

 perforated by abundant genuine pores of very great variation in size (from 

 10 ix to 100 ix in diameter). The oscules are about 2 mm in diameter and 

 about 3 cm apart, center to center. 



Text Figure No. 32. Two of the spicules 

 (oxea) of Halidona ligidata, X 781. 



There is no ectosome other than the above-mentioned dermis, and the 

 endosome is the usual fibro-reticulation of the family Haliclonidae. 



The skeleton consists of spongin fibers, about 20 ll to 60 ll in diameter, 

 cored by oxeas which range from 3 [x by 68 /x to 4 \x by 72 fx. 



The species with which the present specimens are here synonymized was 

 first described as Chalina ligidata by Whitelegge, 1901, page 74, from Aus- 

 tralia. Whitelegge does not describe the type of dermis that is here found, 

 and it may be possible that a new species should be erected for this sponge, 

 which is so very characteristic of the fauna of the island of Guam. 



