Anatomy of Gorgoxio.^. 117 



Spicules. These are all colorless and present some decid- 

 edly characteristic forms. They tend to assume hi-, tri- and 

 quadri-partite forms, PI. II, figs. 14, 13, 15, but perhaps the 

 most striking!}' characteristic is the papilio-form spicule (fig. 

 14), which is more abundant than any other one form. 



The spicules are eminently tuberculate. When they are 

 tri- or quadri-partite they appear to be composed of three or 

 four simple spicules with their bases fitted together so that 

 their juncture presents a cruciform mark as seen in figs. 11 

 and 15.' They seldom exhibit any marked departure from a 

 bilateral symmetry as is the case in Muricea and Eunicea. 

 These tri- and quadri-partite spicules usually present another 

 well marked characteristic in the shape of large tubercles im- 

 planted on the surfaces of each part near its base. These 

 quadrate tubercles thus occupy the angles joined by the cross 

 which marks the juncture of the parts. Simple fusiform and 

 double conic spicules are also met with in this species (PI. II, 

 figs. 12, 16). 



Upon focusing down to the center of a large spicule a con- 

 centric lamellate structure is seen with dark lines radiating 

 from the center. These latter I am unable to interpret. Fig. 

 17 very fairly represents the appearance indicated. 



The spicules of this species are evenly and profusely dis- 

 tributed throughout the mass of the coenenchyma (PI. II, 

 fig. 3). They are quite regular in size and do not seem to 

 present any tangible difference in different parts of the zoan- 

 thodeme. The amount of calcareous matter is decidedly 

 greater in this than in the preceding species, although P. 

 dichotonia is much more flexible than B. asbestinuin. 



Basal Substance. This is much less in relative quantity 

 than in Briareuni ashestinum owing to the preponderance of 

 spicules in the coenenchyma. As its structure is apparently 



I " Les spicules . . . formes par la reunion de quartre petits cones 

 obtus, juxtaposes par leur base. Le point de reunion laisse deviner des plans 

 de separation que se manifestent d la lumiere transmise par deux lignes ob- 

 scures se croisant d angle droit."' Contribution a I'Anatomie des Alcvonaires. 

 Pouchet and Mvevre (p. 292). 



