iSH 



NEW GENERA OF MONAXONID SPONGES, 



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Text-fig.3. 

 Isociella flabellata. a, skeletal styli ; b, dermal styli; c, basal ex- 

 tremities of dermal styli, more highly magnified; d, isochelse, 

 often more or less contort, and frequently passing into anisochelse. 



viduals less than 400/a in length or less than about 15/x in 

 stoutness are scarce. Among the styli, occasional modifications 

 thereof in the form of strongyla occur; these are of lesser aver- 

 age length than the styli — the shortest one observed measuring 

 only 290 /x long. 



