140 Natural History Bulletin. 



ed calicles, reaching even over the surface of the caHcular 

 lips. Here, however, they are more thinl}^ distributed in order 

 to permit of the motion of the caHcular lips. These spicules 

 are all white, or rather colorless. 



2d. Larger tuberculate fusiform spicules which are of two 

 well marked sizes, according to the position which they occu- 

 py. The large ones are handsome, symmetrical or arcuate 

 and are among the largest, or rather longest, spicules encoun- 

 tered.' They may be either colorless, in which case they 

 occupy a position in the coenenchyma immediately under the 

 "cortical layer" spoken of above, or of a rich purple color, 

 in which case they are near the axis cylinder. The colorless 

 ones are found in the coenenchyma of the calicle w^alls, stand- 

 ing parallel to each other and surrounding the calicle, to which 

 they thus contribute an effective support.^ Other large color- 

 less spicules are found in various positions underlying the 

 cortical layer in all parts of the branches. Beneath these are 

 a few large purple spicules, the purple color becoming more 

 intense as we pass toward the center of the branch. Around 

 the axis cylinder, there is a thick mass of intensely pur- 

 ple spicules which are generally much smaller than the others 

 of the same shape.' They are placed, as a rule, with their 

 long axes parallel to the axis cylinder. 



Many of the spicules of this species appear to contain a 

 central cavity, sometimes of considerable extent. 



The tubercles on the surfaces of the large spicules, are 

 often quite complicated in form, as is illustrated in fig. 27, PI- 

 VII. They appear to consist of a short thick shaft or pedicel 

 upon which is mounted an expanded head consisting of several 

 irregular projections arranged around a central disk. These 

 tubercles, or rather the shafts spoken of, appear to contain 

 axial cavities. 



1 In some instances thej are as much as 2 m m. long. 



2 See PI. IV, fig. 5, f, f. 



3 See PI. IV, fig. 2, b. 



