58 PROCEEDINGS OF THE NATIONAL MUSEUM vol.81 



In the vicinity of Monterey H. sinapiuni occurs very rarely, if at 

 all, though similar ecological situations are found. E. F. Ricketts 

 collected a specimen, July 24, 1926, in a tide pool near Hopkins Ma- 

 rine Station, which was like the southern California specimens in all 

 ways save one ; it has spicules up to 14;* by 380]^. Having but the one 

 specimen I hesitate to denominate this a new variety, though in no 

 southern California specimen do I find spicules so large. The condi- 

 tion of the specimen is such that any identification of it must be 

 provisional. 



U.S.N.M. No. 21395 represents the only sponge from lower than 

 intertidal zone that 1 can refer to sinapiiMin. It deserves special 

 mention, as its spicules are notably smaller, namely, but 6ju, by 205/i 

 at the largest, 5/x by 195/1, for an average of apparently mature 

 styles, but with only a few of the very small presumably develop- 

 mental forms. It was dredged by the University of Southern Cali- 

 fornia in 5 meters near Seal Beach (near San Pedro), just offshore 

 from locations where sinapium is abundant intertidally. Is the small 

 spicule size an ecological modification, or is this a different species? 

 Its resemblance to my Plymouth specimens of H. caruneula merits 

 comment. Having but the one specimen, no positive decision can be 

 made, but my opinion is that it is an aberrant individual of a species 

 normally intertidal, perhaps modified by the environment. This 

 species is found associated with oysters more than any other one 

 large organism. Numerous other specimens were examined. 



Deseinption. — Shape, amorphous to massive to encrusting, often 

 with digitate processes. Size, up to about 10 cm high, 20 cm in 

 diameter. Consistency, very soft. Color in life, bright yellow, some- 

 times with orange tints; preserved, drab. Oscules, often on raised 

 processes; diameter, about 2 mm. Pores, minute, very contractile. 

 Surface, superficially smooth, with scattered low conules less than 

 1 mm high. 



Ectosomal specialization in the form of a thin, transparent, fleshy 

 dermis. It contains but few spicules. Endosomal structure, " crumb- 

 of-bread," with spicules mostly in confusion, but here and there 

 organized into tracts, mostly directed vertically, points of the styles 

 up. These tracts expand distally into subdermal brushes in a manner 

 that may be described as axinellid, but is also found in most 

 Mycales and some Biemnas, and may indicate axinellid relationships 

 for those genera. 



Principal spicules, styles (fig. 29) ; size up to 9ju, by 340/*, with 

 moderately numerous smaller forms. 



Remarks. — It is doubtful whether this is a new form, but as it 

 seemed impossible to be absolutely positive of identifying it with 

 any of the known species I applied a distinctive name to it so that 



