230 THE AMERICAN MUSEUM JOURNAL 



some of which are shown in Fig. 13. Those having one or 

 two axes may be straight, curved, or bent at various angles. 

 They may be pointed, rotmded or knobbed at one or both ends. 

 They may be smooth or spined. Spicules having a greater 

 nvunber of axes may also have their arms pointed, rounded 

 or^^knobbed, or each arm may be branched, either once or twice, 

 or to such a degree as to present a great variety of star-like 

 figures. Spicules occasionally assume extremely odd shapes. 

 Some look like tiny cuff-buttons, others like anchors, horseshots 

 and hooks of peculiar design, while still others are coiled like 

 springs. As regards size they may be divided into two classes: 



FIG. 14. — A DICTYONID SPONGE (Farrea occa Carter) 

 With rigid lattice-like skeleton. 



megascleres, or large spicules, and microsderes, or small spicules. 

 The megascleres form the main supporting structure of the 

 skeleton and are bound together in long fiber-like bundles which 

 are either parallel, or cross each other so as to form triangular or 

 square meshes. They are sometimes entangled and interlaced 

 in all directions like felt, clinging to each other with their hooks and 

 projections. In the Dictyon id sponges (Fig. 14) the megascleres 

 are of three axes at right angles to each other and are arranged 

 with^ points overlapping During the life of the sponge these 



[16] 



