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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 81 



one another except at the base. Principal, or ascending, fibers about 

 200/x in diameter. 



Interstitial spicules, subtylostyles (fig. 56, B) \ size, 3/* by 260/t 

 to 5/A by 300/A. Coring spicules, smooth styles (fig. 56, A) \ size, 

 27ja by 350/x to 33/a by 430/i to 30/a by 475/^. Echinating spicules, acan- 

 thostyles (fig. 56, G)\ size, 5/* by 100/x to 8/x by lOS/n. First micro- 

 .scleres, palmate isochelas (fig. 56, Z>) ; length, 24/;i to 28/*. Second 

 microscleres, large toxas (fig. 56, F) ; size, 2>ix by 40|U, to 7//, by 72^.. 

 Third microscleres, small toxas (fig. 56, E) ; length, li/x to 22/;.. 



Figure 56. — Microciona parthena de Laubenfels, X300 



Remarks. — The nearest relative of this form seems to be Micro- 

 ciona microjoanna from central and southern California, which 

 differs in having chelas of very different shape, toxas of only one 

 size range, a quite different shape, and coring styles very much 

 smaller. 



Genus CLATHRIOPSAMMA Lendenfeld 



CLATHRIOPSAMMA PSEUDONAPYA de Laubenfels 



ClatJmopsamma pseudonapya de Laxjbenfels, 1930, p. 28. 



Holotype.—U.^.'^M. No. 21436; B.M. No. 29.8.22.19. 



Type locality. — The one specimen is from Pacific Grove, Calif., 

 intertidal, June 30, 1926. 



Description. — Shape, encrusting. Size, up to 1 cm thick, 4 cm in 

 diameter. Consistency, spongy to fragile. Color in life, yellow; 

 preserved, pale drab. Oscules and pores, not evident. Surface, su- 

 perficially smooth, with irregularly scattered conules about 1 mm 

 high. 



Ectosomal specialization, a dermal membrane, about 50/* thick; it 

 is fleshy, detachable, and contains some tangent spicules of the sorts 



