308 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



2. Strongyle. Stout, smooth, slightly curved; diminishing slightly 

 in size toward the ends; 700-1,750 \x long, 80-40 [x thick. Most 

 abundant spicule in the skeletal bundles. 



3. Oxea. Smooth, 500-1,200 [x long, 12-25 [x thick. Common in 

 the skeletal bundles. 



4. Sterraster (pi. 46, tig. 2), Ellipsoidal; distinctly but not greatly 

 flattened; 220 \k long, 175 pt, wide, 112 \i thick. The individual rays 

 of the adult spicule are small. In surface views (end views of 

 rays) they appear as minute polygons, with 3 to 5 sharp angles, 

 2-3 [i in diameter; as a rule so closely set that the intervening spaces 

 appear as lines which form a network; some of the rays farther 

 apart. 



The sterrasters in this sponge are thick as compared with those 

 of most Erylus species, but in some specimens of E. lendenfeldi 

 Sollas (see Lendenfeld, 1903, p. 85; Dendy, 1916, p. 257, says they 

 are "much flattened"), E. topsenti Lendenfeld (Lendenfeld, 1903, 

 p. 87), and in E. polyaster Lendenfeld (1906, p. 306), the ratio of 

 thickness to the other dimensions is about the same as in E. cornutus. 



There seems to be no essential difference in the structure or de- 

 velopment of the sterraster between this species of Ei*ylus and a 

 Geodia. All stages in the development of the spicule are abundant 

 in the interior. They are all spheraster-like — that is, consist of a 

 center with rays, the rays gradually fusing as they elongate. No 

 very flat rays and no smooth stage (aspidaster) are to be seen. Stages 

 30, 50, 70, 80, 100, 120, 140, 200 \l in diameter were measured. They 

 all conform to Sollas' scheme of the development of the sterraster 

 (1888 p. lxiv). 



5. Microrhabd (pi. 45, fig. 5, a). Straight, or sometimes a little 

 curved, usually centrotylote, but very slightly so; diminishing in 

 thickness toward the ends, which are rounded; 25-50 [x long, about 

 6 [i. thick. Abundant in the dermal membrane; present but rather 

 scanty in the walls of the chone-canals. 



6. Strongylaster (pi. 45, fig. 5, b). Rays stout, short, and trun- 

 cated; ends as a rule rounded, instead of being squarely truncated, 

 frequently notched in an irregular way. Total diameter 20-28 [/., 

 number of rays 5-7. Abundant throughout choanosome, especially 

 in the canal walls. 



II olotype.— Cat. No. 21262, U.S.N.M. 



Genus GEODIA Lamarck (1815), emend. Lendenfeld (1894). 



Geodia I.amakck, part plus Cydqniim\ Flemming, Sollas 1888. 

 Geodia Lamarck, emend. Lendenfeld, 1S94, p. 46. — Lendenfeld, 1903, p. 

 104.— Part Dendy, 191G. p. 254. 



Both afferent and efferent cortical canal spaces are typically inde- 

 pendent chone-canals, the roofs of which are cribriporal. Frequently 



