ART. 4 SPONGES OF CALIFORlSriA de LAUBENFELS 57 



Consistency, fragile. Color in life, orange to green; preserved, 

 nearly white. Oscules, raised; diameter, about 1 mm. Pores, 

 minute. Surface, superficially smooth to tuberculate. 



Ectosomal specialization strongly marked, consisting of a dermal 

 crust, about 200/i thick, of tangentially strewn spicules, not differ- 

 ing, however, from those of the endosome. This is underlaid by 

 such extensive subdermal cavities as to be rather readily separable. 

 Endosomal structure, " crumb-of-bread," most of the spicules strewn 

 without order in the flesh, but there may be spicule tracts in a 

 groundwork that is not reticulate. Histological details: I find 

 spherical flagellate chambers 30/x to 40/x, in diameter. Principal, or 

 ascending, tracts about 45/t in diameter. 



Figure 28. — Halichondria panicea (PaUas), X300 



Principal spicules, oxeas (fig. 28) ; size up to 11/x by SOO^n. As is 

 characteristic of the species and genus, there is no definite size range 

 of spicules at all, but all sizes — from the largest down — are found 

 intermingled in confusion. 



RerruLThs. — In species so lacking in positive characters as this, it 

 is difficult to be certain whether the similar specimens from various 

 parts of the world are conspecific. 



Genus HYMENIACIDON Bowerbank 



HYMENIACmON SINAPIUM de Laubenfels 



Hifmeniacidon sinapium de Laubenfels, 1930, p. 26. 



Holotype.—V.S.^M. No. 21456; B.M. No. 29.8.22.21. 



T-t/pe locality. — Newport Bay (near San Pedro), Calif.; intertidal. 



Occurrence. — This species is abundant along the rocky, surf-beaten 

 portions of the coast of southern California at nearl}^ every point I 

 have visited. It is the most abundant sponge on the oyster beds in 

 Newport Bay, where the w^ater often becomes quiet and very warm. 

 It is found in various places up the stream that enters the bay, where 

 it must be in brackish water at low tide during rainy weather. It 

 grows even where the water is almost opaque with suspended mud, 

 where at low tide it is exposed to the very ardent rays of the southern 

 California sun, and where it is always chilled by the very cool waters 

 of the open ocean, I have vainly sought any difference in spicules, 

 form, color, or any other quality that varied as a factor of any of 

 these environments. 



