BY E. F. KALLMANN. 



407 



fibres, seldom more than 20 /x broad, which here and there are 

 partially connected by loose spicule-bundles. The dermal mega- 

 scleres are similar to those of the interior. Scattered micro- 

 scleres— anisochelfe, sigmata, and trichodragmata— are compara- 

 tively scarce; the chelae do not form rosettes. In the dermal 

 membrane, chehe and sigmata are more frequent than in the 

 choanosome, and trichodragmata apparently do not occur. 



Scattered through the sponge are 

 small patches of foreign material, com- 

 prising sand-grains, spicule-fragments, 

 foraminifera, etc. ; and immediately 

 surrounding each of these patches there 

 occur a few fibres and spicule-bundles 

 such as elsewhere are seldom met with 

 except in the superficial (i.e., the dermal) 

 skeleton. These patches presumably 

 occupy spaces (lacunm relictce) origin- 

 ally due to, and now almost obliterated 

 by, the fusion of once separate pro- 

 cesses of the sponge, as suggested above 

 — or, in other words, are, strictly speak- 

 ing, external to the sponge — and, on 

 this view, the spicule-bundles and 



fibres referred to, that occur seemingly Fig. H.—Mycale serpens, a 

 within the sponge, are really portions lylostyli 

 of the dermal skeleton. To a miscon- 

 ception arising from the presence of 

 such fibres and bundles in the preparations examined by him, 

 was probably due Lendenfeld's incorrect description of the main 

 skeleton as consisting of "longitudinal spicule-bundles,* which 

 are on an average .... 0' 15 mm. apart," etc. 



Spic7des. — {a)T\iG tylostyli are straight or (less frequently) 

 variously curved, gradually sharp-pointed, slender spicules with a 

 well-developed elongated phyma; the shaft is slightly narrower 



* By " spicule-bundles,'' Leudenfeld always (in the "Catalogue") means 

 "fibres composed solely of spicules" ; this is most clearly shown in his 

 description of Sideroderma zittelii. 



of tylostyli 

 c, Sigmata. 



a', Basal ends 

 6, Anisoclielse. 

 d, Trioiiites. 



