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PROCEEDINGS OF THE ISTATIOISTAL MUSEUM 



VOL. 81 



cladomes may be actually projecting beyond the surface of the 

 sponge, {d) A type of spicule (fig. 10, A, B, G) that is typically a 

 mesoprotriaene but may have a very small epirhabd or none ; may be 

 protriaene or orthotriaene; or may be triaene, diaene, or monotriaene. 

 This occurs usually or always in the spicule fur, and therefore tends 

 to be lost when that is rubbed off. Its frequency and shape seem to 

 be the most characteristic items distinguishing California Geodias. 

 I find rhabd diameter 11/^ to 48/i. Lendenfeld reports 7/a to 12jw. (e) 

 Dermal small oxea or styles (fig. 10, i), diameters 2ju. to 13ju,, lengths 



TiGURB 10. — Oeodia mesotriaena Lendenfeld : Spicules A to M, X 80 ; others, X 1,333. 

 O, a developmental form of the sterraster, of which N — to the same scale — can only 

 show a small bit of the surface. Hj, pointed end, which is the same for the oxeas and 

 the esactines of the plagio spicules. /, esactine of the other polyactinal megascleres 



usually about 200/i. (/) Sterrasters (fig. 10, M, N, O), greatest 

 lengths ranging from 65/a to llS/x, least diameters from 42/i to 83/x, usu- 

 ally 50/x by 70fji by 60^. {(/) Strongylospherasters (fig. 10, P, Q), 4ju. 

 to 15/i, in diameter, (h) Oxyspherasters 6/t to 24jli in diameter, (i) 

 Oxyeuasters 9jx to 35/* in diameter (fig. 10, R) . It might be much more 

 accurate to say there are small asters of great variability, the ends of 

 the spines varying from strongylote (rounded) to oxeote (sharp) 

 but usually more rounded in the smaller and sharper in the larger. 

 A centrum may be present varying from comparatively very large to 

 absent, but most conspicuous in the smaller asters. The rays seem 

 always to be spined, but the spines vary from almost invisible to very 



