6 THE SPONGES OF THE WEST-CENTRAL PACIFIC 



scopic and so contractile that in preserved specimens they usually are found 

 to be closed. The oscules are commonly about 1 cm in diameter, but may be 

 as large as 2.5 cm. In the lobate specimens, they are commonly located at the 

 apex of the elevations; in a sponge as much as 15 cm in diameter there will 

 be from 5 to 10 oscules. In the Ponape specimen there were just three, one 

 for each of the connected cone-shaped lobes. There is no raised rim around 

 the oscules. 



The ectosome of this species is a thin dermis about 10 fx thick, and it is 

 noteworthy that it comes loose with extreme ease. One need only squeeze 

 the newly collected sponge a dozen times in the hand, whereupon the skin 

 begins to come loose in large flakes and is soon all removed. From macerat- 

 ing specimens it melts away almost immediately. 



The endosome is a typical Spongia-type. That is to say, the flagellate 

 chambers are more abundant, crowded more closely together, and more con- 

 spicuous than in nearly any other genus of sponge. They are about 20 ll to 

 30 fj. in diameter and are spherical. The entire endosome is permeated by 

 the dense fibro-reticulate skeleton. The ascending fibers of this species are 

 rather scarce, about 40 jx to 50 p. in diameter, and are crowded with small 

 foreign inclusions, such as grains of sand and fragments of foreign spicules. 

 The commoner fibers, which might possibly be called secondary, are about 

 15 ix in diameter. They outline meshes which are polygonal, but irregular in 

 size, 100 /x being a rather common diameter. 



This is obviously a silk sponge of the finest commercial type, very closely 

 related to those which occur near the east end of the Mediterranean Sea. It 

 is so closely related to the type of the genus, Spongia officinalis, typical sub- 

 species, that were it not a commercial-type sponge, I should not bother to 

 erect a new subspecific name. This action is taken, however, in order that 

 the distinctive appellation may be available in the literature. The basis of 

 separation may be taken as the tendency to lobate growth, which is less preva- 

 lent in Mediterranean sponges. 



Comment may be made that this species has the same odor as the related 

 Spongia from the West Indies. 



The subspecific name is derived from the native Marshallese name for 

 this organism. 



Spongia zimocca Schmidt 

 Subspecies irregularis Lendenfeld 



Text Figure No. 2 



This species is here represented by the following: 

 U.S.N.M. No. 22882, My No. M. 181, collected on August 1, 1949, by diver 

 in eastern Ponape (Matalanim) from a reef in the lagoon near an en- 

 trance to the lagoon from the open ocean. The depth was 5 meters, and 

 the substrate was (the under side of) dead coral. 



