BY R. VON LENDENFELD, PH.D. 537 



margins of the curved lamellae. These processes may be flattened 

 or cylindrical, but they never reach a large size. The lamellae 

 enclose each other to a certain extent, so that a flower shaped 

 form is produced. 



The largest specimens measure 80 mm. in width and GO mm., in 

 height. The lamellte have a very uniform thickness of 8-10 mm. 

 The digitate processes may attain a length of 75 mm. 



Colour. 

 The sponge is, alive and in spirits, of a brownish grey colour. 



Surface. 



The surface is pex'fectly smooth. There are no conuli. With a 

 magnifying glass a very regular network of sand grains can be 

 detected similar to the one which is described in this paper of 

 Euspongia canaliculata. 



In the meshes of this network we find the pore-sieves, which 

 are slightly depressed and perforated by numerous small pores. 



The oscula are disposed in an irregular line on the free margin 

 of the lamella. A few are also met with on the broad sides. They 

 measure about 1 mm., across, are circular, and slightly elevated 

 above the surrounding surface. The oscula are numerous. 



Canal System. 



Below the outer skin a reticulation of anastomosing tangental 

 canals are met with, which repi'esent the subdermal cavity. The 

 pore-sieves with their numerous pores cover the sub-dermal cavities 

 in the shape of a thick skin, which is pervaded by numerous narrow 

 canals as in Euspongia silica ta. 



The skin has a thickness of 0-22 whilst the pores and canals 

 possess an average width of 0-03 mm. The pores can apparently 

 be entirely closed by the sponge, although some of them are always 

 seen open. 



The greatest number observed in one pore-sieve was 16. 



These canals are not very large, they measure on an average 

 0'2 mm. in diameter and are oval or irregular in transverse section. 



