AKT. 12 HEXACTINELLID SPONGES OKADA 105 



Specimen C is elongate-sacciform, 95 mm high, with an oval 

 oscular opening. The broadest part of the body is situated beloAv the 

 middle of the stock and measures 38 mm; the basal part measures 

 only 14 mm. The thickness of the wall is nearly the same as in speci- 

 men B, measuring 2 mm in the middle and 1 mm in the lower part. 



Specimens D and E are similarly shaped and have bent bodies 

 (at the base) 75 mm in height. The diameters of the oval -shaped 

 osculum are 13 mm and 20 mm, respectively. The broadest part of 

 the entire stock measures 26 mm to 30 mm, and the extremely nar- 

 rowed stalklike basal region, which is bent toward one side, meas- 

 ures 2 mm to 5 mm in breadth. The thickness of the wall is 2 mm 

 at the thickest part of the entire stock. Both specimens are well 

 preserved, except at their basal ends. The gastral cavity seems not 

 to extend into the extreme end of the basal stalk region but appears 

 close to it. 



Specimen F is the smallest of all, and is tubular or vaselike in 

 form, about 30 mm in height and not less than 8 mm in diameter. 

 The wall is 1 mm thick in the thickest part and becomes gradually 

 thinner toward the outer oscular margin, where it measures 0.8 mm. 

 The circular osculum measures 4 mm to 5 mm in diameter. The 

 prostal marginalia measure 15 mm to 20 mm in length. 



The greater part of the entire stock of specimen G is broken, the 

 remaining part measuring about 35 mm high and 15 mm broad. 



Specimen H (holotype, U.S.N.M. No. 22161) is a cup-shaped 

 sponge, 65 mm in height; the wall at the middle of the entire stock 

 measures 2 mm thick. The greatest breadth of the sponge appears 

 in the superior region ; near the lower part of the oscular margin it 

 measures 40 mm. 



Sficulation. — The parenchymal principalia are bowlike oxydiactins 

 with tapering or straight raj^s, which subterminally are occasionally 

 smooth. They may attain a length of 6 mm and a thickness of 102/x 

 in the middle, but are usually smaller. The middle is not externally 

 marked by a swelling. There are no points worth special mention 

 regarding the slender parenchymalia. 



The prostal marginalia present on some specimens are needlelike 

 oxydiactins, which may be 10 mm to 17 mm or more long and 12/a 

 to 77/x thick. The rays gradually taper toward the end and are 

 subterminally minutely tuberculated. 



The prostal basalia are represented in some specimens. They are 

 nearly the same length as the prostal marginalia but are rather 

 strongly tuberculated at the ends and not extremely narrowed or 

 pointed. 



The large prostal pentactins are present usually in the upper two- 

 thirds of the entire stock ; they seem to become lost as somehow they 

 are shed off in the lower parts. Diactinic prostalia were not ob- 



