32 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 1 1 



Distribution. — The same. 



Material examined. — 

 Sta. 609-36 San Benito 3-24-36 Shore 



Remarks. — The canals found in this sponge give it the superficial 

 appearance of being organized into tracts. If this were true, it might be 

 placed in the genus Adreissa. 



The peculiar modification of the styles is unique for the genus. 



Hymeniacidon sinapium de Laubenfels 

 Plate 56, Fig. 112 



Hymeniacidon sinapium de Laubenfels, 1930, p. 26. 



Diagnosis. — This sponge is typical of the family and genus, having a 

 thin fleshy dermis and an endosomal structure in w^hich the spicules are 

 mostly in confusion, although occasional vague tracts, made up of styles 

 points upward, are found. 



The sole type of spicule is a style size 9 ju. by 350 fi. 



II olotype.— U.S.N. M. 



Type locality. — Newport Bay, California. 



Distribution. — Southern California to the Gulf of California. 



Material examined. — 

 Sta. 1041-40 GuaymasBay 1-23-40 Shore 



Remarks. — In the California specimens the styles are about a third 

 larger on the average than in the Gulf specimens. 



Genus OXEOSTILON Ferrer-Hernandez 



Oxeostilon oxeon, new species 



Plate 57, Figs. 113, 114; Plate 58, Figs. 115, 116 



Diagnosis. — This sponge is 3 cm by 2 cm by 1 cm, drab when pre- 

 served, and corklike in consistency. The surface is covered with peculiar 

 hornlike protuberances. These are 2 mm high and about 1 mm at the base. 

 A distinct surface membrane is present, although it is less than 100 /x 

 thick. It is easily detachable and there are extensive subdermal cavities. 

 On areas which retain the surface membrane no pores or oscules are 

 visible, but when the membrane has been lost, openings 1 mm in diameter, 

 which form grooves on the exposed surface appear. Often the openings 

 merge into one another. 



The megascleres show great variety in size and are frequently bent 

 or curved. Both oxeas and styles are present. Representative measure- 

 ments are 30 fx by 600 ix, 40 ix by 800 fi, and 40 /x by 900 fx. The styles 

 and oxeas are, in general, about the same size but occasionally oxeas were 



