102 BIOLOGICAL SURVEY OF 



Skeleton. The main skeleton is a rather diffuse and irregu- 

 lar polyspicular reticulation. Single spicules contribute in 

 many places to the main skeleton. The dermal skeleton is 

 formed of large and small bundles of spicules lying horizon- 

 tally or in a more or less erect position. Single spicules are 

 also found scattered in the dermal membrane. 



Spicules. Megascleres. 1) The skeletal spicules are styli 

 with an even slight curve nearer the rounded end. They vary 

 slightly in length in different individuals, although their size 

 is quite constant within the specimen. These styli range in 

 size from .364 mm. to .486 mm., with a mode of .405 mm. 2) 

 The dermal spicules are usually straight, sometimes slightly 

 curved, tylota. At each end they have a distinct, somewhat 

 elongated swelling, which passes evenly and gradually into 

 the shaft of the spicule. The tylota vary in length from .284 

 mm. to .364 mm., with a modal length of .324 mm. 



Microscleres. Raphides are present in abundance and are 

 scattered as well as in bundles. They have one end abruptly 

 pointed, while the other end tapers gradually into a long, very 

 fine point. These spicules exhibit a 'roughness' in distinction 

 to 'spination' or 'microspination.' The rhaphides vary in 

 length from .12 mm. to .284 mm., with the mode at .243 mm. 



Geographical distribution. Davis Strait (Lundbeck), off 

 Newfoundland (Topsent) ; Mount Desert Region. 



Stylotella Ledenfeld 

 Stylotella simplissima (Bowerbank) 



Bowerbank (1874, p. 324, pi. 90, figs. 1-3) (Raphiodesma 

 simplissima). 



This species was taken once at Station 119. There w^as only 

 one specimen. Taken on hard bottom in 42 to 60 feet of 

 water. 



This sponge forms a thick incrustation with an uneven sur- 

 face, due to the presence of grooves, mounds, and cones. The 

 oscula are few in number, inconspicuous, and small. These 

 do not exceed a millimeter or two in diameter and are usually 

 situated at the apex of the cones. 



