THE SPONGES OF THE WEST-CENTRAL PACIFIC 27 



The ectosome consists of a cartilage-like cortex about 1 mm thick, but 

 not readily detached or separated from the underlying material. In the endo- 

 some, brown fibers show plainly to the naked eye in a ground mass or matrix 

 of jelly. When the latter is studied in thin histologically prepared sections, 

 one finds here and there scattered clusters of typical flagellate chambers 25 

 to 30 (i in diameter; but even larger areas of the jelly are totally devoid of 

 any flagellate chambers. Widely distributed, but particularly abundant in 

 these areas which do not have chambers, are numerous embryos, at first 

 thought to be sand grains because of their pale color. They are about 240 

 to 300 /x in diameter. Perhaps the unusual histological conditions, as evi- 

 denced by the lack of flagellate chambers in many regions, may be due to the 

 fact that the sponge was in a particularly active stage of reproduction at the 

 moment of collection. 



The skeleton consists of a reticulation of clear, stratified fibers, but with- 

 out any central pith. Some, which may be regarded as primary, are as large 

 as 70 fi in diameter. More of them are as small as 30 p. The meshes are 

 exceedingly irregular in size and shape; some are small and round, scarcely 

 40 p in diameter. There are all intergradations between these and larger 

 polygonal meshes 200 to 300 p. in diameter. 



There are three other species now in the genus. Of these, hermanni is 

 not at all well known, and tubulosa is characterized by a definite tubular 

 shape. This latter was described by Burton, 1937, page 42, from southern 

 India. Closest to chondrodes is the type of the genus, S. pidchella, described as 

 Spongia pulchella by Sowerby, 1806, page 87. This is a laminate species 

 from deep water in the North Atlantic, and its soft parts are particularly ill 

 known. Its skeleton is much more regularly reticulate than that of chon- 

 drodes, and there is no indication that it has the peculiar cartilage and jelly. 



The species name chondrodes is selected from a Greek word for "car- 

 tilage." 



GENUS D RUIN ELLA Lendenfeld 

 Druinclla tyroeis, new 



Text Figure 14 



This species is here represented by the following: 

 U.S.N.M. No. 23052, My No. M. 431, here designated as type, collected on 

 August 1, 1949, by diver in eastern Ponape (Matalanim) from a reef 

 in the lagoon near an entrance to the lagoon. The depth was 5 meters, 

 and the substrate was dead coral. 



Other specimens of this sort were studied in the lagoon of southwest 

 Ponape (Kiti) on August 3, 1949, but not preserved. The species, however, 

 is definitely not common. 



This is an incrusting sponge, 7 mm thick, covering about 5 square cm. 



