FORAMINIFERAN AND OTHER CORALS 195 



eyes occur on the dorsum of the reddish cephahc area. 

 The anterior (thoracic) membrane is more deeply tinted in 

 front than behind. When in full vigour the pure white of 

 the calcareous tubes, the scarlet of the anterior region 

 which projects beyond them, and the pale greenish yellow 

 fans with their opaque tips make a picture at once beautiful 

 and characteristic." 



Reference has already been made to the world-wide 

 distribution of this beautiful and interesting tubicolous 



Fig. 100. — Filograna implexa. A small part of the mass of serpentine tubes. 



X 5 diams. 



worm, but to avoid misunderstanding it should be stated 

 that the species and varieties which have been described 

 by various authors under the generic name Salmacina are 

 here included in the genus Filograna. The only essential 

 difference which was supposed to separate the two genera 

 was the presence of an operculum to close the mouth of the 

 tube in Filograna and its absence in Salmacina, but Mcintosh 

 has shown, in a recent paper, that this character is so 

 variable, even in specimens from the same locality, that it 

 is quite unreliable for generic distinctions and considers 



