ACANTHASCUS ALANT. 159 



base. Total height, 190 mm. Greatest breadth of body, 133 

 mm.; lesser breadth in the same region, 104 mm. Stalk-like 

 base, about 60 mm. in greatest breadth. Superiorly the body-wall 

 closes in towards the thin oscular margin which is apparently 

 simple-edged. The irregularly roundish osculum is about 60 

 mm. in diameter. The deep gastral cavit}'- extends into the 

 stalk-like base. The body-wall in the lower part is as thick 

 as 35 mm. 



Notwithstanding the lacerated condition of the external 

 surface, it can be ascertained that this was by no means smooth 

 but must have shown a number of irregular hillock -like or ridge- 

 like elevations, judging from what appear to be their rests. The 

 more prominent of the elevations may have been 10 mm. high, 

 as measured from the bottoms of adjacent depressions. Possibly 

 their summits were originally provided with diactinic prostalia as 

 in other sj)ecies of the genus, but no such spicules have been 

 found preserved in the specimen. 



Fortunately there has remained the ectosome in some places, 

 though in small patches (PI. X., fig. 23). It is uneven, being- 

 much creased. The minutely and more or less regularly quadrate 

 meshed dermal lacework is exceedingly delicate ; it is supported 

 l)elow by fine intersecting hypodermal strands, mostly under 0.1 

 mm. in thickness, which pursue a sinuous course. Over the 

 interaperturai spaces, as also over the external prominence, the 

 ectosome is generally in close contact with the choanosome, so that 

 it can not be very clearly distinguished. Where it has fallen 

 off, the sponge-surfîice appears somewhat crisp-hairy on account 

 of the dishevelled fibers of the parenchymal strands. The stalk- 

 like base presents the usual fibrous texture. 



The incurrent canalar apertures measure mostly under 5mm. 



