THE MOUNT DESERT REGION 103 



Skeleton. This is composed of 'multispiculous fasciculi,' 

 which are exceedingly variable in width and length, and these 

 bundles are irregular disposed. Usually they are no longer 

 than a spicule in length and there is no discernible tendency 

 for them to be organized into fibers or tracts. Bowerbank 

 emphasizes the coincidence of the heads and points of all the 

 spicules within a bundle. A tendency toward such an ar- 

 rangement is noticeable but not invariably found in the speci- 

 mens from this region. 



Spicules. These are long, slender, gradually tapering, usu- 

 ally curved styli. The curve or bend is sometimes quite 

 abrupt and usually nearer the blunt or head end. These 

 spicules are almost all of one size and measure .324 mm. in 

 length. Bowerbank mentions and figures two types of styli 

 which are identical except for a difference in their widths. 

 The more slender styli are recorded as variable in size and 

 composing the dermal membrane, whereas the stouter styli, 

 although variable in length and breadth, compose the skeletal 

 fasciculi. In the specimens from this region these slender 

 styli of all sizes are quite abundant in all parts of the sponge. 

 As they show all gradations in size between the smallest and 

 largest spicules and are otherwise identical, it would appear 

 that they are nothing more than developmental forms. 



Remarks. Verrill has recorded the occurrence in Casco 

 Bay of Stylotella pannosa, but did not give any description 

 of it. If Verrill 's determination of his specimens be correct, 

 it can be distinguished from Stylotella simplissima by its spic- 

 ule length (.14 mm.) in addition to other minor features, 

 according to Bowerbank 's description of S. pannosa. 



Geographical distribution. Mount Desert Region. This is 

 the first time that this species has been described from the 

 Atlantic coast of North America, although the occurrence of 

 the genus {Stylotella pannosa) has been recorded by Verrill 

 for Casco Bay and by Wilson {Stylotella heliophila) for Beau- 

 fort, North Carolina. 



