98 



PEOCEEDIXGS OF THE NATIONAL, MUSEUM 



TOL. 81 



ACANTHASCUS CACTUS F. E. Schnlze 



Acanthascus cactus F. E. Schuxze. Abh. kou. preiiss. Akad. Wiss. Berlin, 1886, 

 p. 49: Rep. Toy. Challenffer, vol. 21, p. 148, pi. 57, figs. 1-7, 1887.— Ijima, 

 Annot. Zool. Japon., vol. 1, p. 48, 1897. — F. E. Schulze, Sitz-ber. kon. preuss. 

 Akad. Wiss. Berlin, vol. 26, p. 551, 1897. — Ijima, Journ. Coll. Sci. Imp. 

 Univ. Tokyo, vol. 18, art. 7, pp. 140-158, 296, pi. 11, figs. 16-22, pi. 12, figs. 

 23-37, 1904. 



Specimen A expands somewhat superiorly in such a manner as 

 to take on a funnellike shape, as shown in Ijima's Contribution IV, 

 page 142, Figure 6, D. Height, 140 mm. Broadest part of sponge 

 body, 70 mm. Xear the basal end it measures 45 mm. As the pre- 

 served sponge is extremely compressed laterally, the exact size of 

 the osculum can not be ascertained. It probably measured 45 mm 

 to 65 mm. The wall of this specimen is thicker than in specimen B, 

 measuring up to 6 mm in the middle of the entire stock. The body 

 is nearly completely preserved, lacking a basal attachment and even 

 a basal plate. The sharply apexed conical elevation of the external 

 surface occurs at various but rather wide intervals, measuring about 

 17 mm high. On the oscular edge there may occur very fine prostal 

 marginalia, which always project singly, without forming small 

 tufts. 



In the smaller specimen (B) the lower parts of the entire stock 

 are much more dilapidated. It measures 76 mm high and 60 mm 

 wide at the broadest part of the sponge. The wall in the middle is 

 about 2 mm thick. There are no numerous conical elevations, as in 

 specimen A. 



Table 21. — Record of specimens of Acanthascus cactus 



Speculation. — The prostal marginalia are not distinct, projecting 

 simply from the thin edge of the osculum. They are very fine 

 diactins, measuring about 2 mm long and 0.5 mm thick in the middle, 

 being smooth on the surface with the exception of both ends. 



xVlthough the simple hexactins in the parenchyme were not seen 

 by previous observers, they were found occasionally in both speci- 

 mens. Paratangentials are of nearly uniform length, being 48/^ long, 

 and the distal and proximal rays 56/a long, and tuberculated on the 

 entire surface. 



As noted by previous authore, the gastralia usually consist of rough 

 pentactins and occasionally of stauractins, but besides these I have 



