ART. 12 



HEXACTINELLID SPONGES — OKADA 



63 



The dermal swordlike hexcactin is somewhat larger than that in 

 the typical species but is smaller than those of the specimens from 

 other stations. The length of the hilt ray is 120^. to 160^. The 

 blade ray is generally more than three times as long, up to 550,a. 

 Guard rays are somewhat shorter than the hilt ray, measuring 88/* 

 to 145)U, in length. 



Specimens B (1, 2, and 3) are beautifully preserved. Measure- 

 ments and numbers of transverse and longitudinal beams are given 

 in Table 17. 



Table 17. — Measurements and numbers of transverse and longitudinal beams of 

 3 specimens (B, 1, 2, and 3) of Euplectella oweni 



1 Exclusive of basal tuft. 



' Ledges included. 



In specimen B, 1, the diameter of the parietal pores is large, meas- 

 uring 1,5 mm. The parietal ledges are prominently developed, 

 being 5 mm high. The broadest part of the body ;s usually situated 

 far below the middle of the entire stock. The wall of the body is 

 thick, attaining 4 mm in the thickest part of the entire stock 

 (excluding the height of parietal ledges). 



S'plculation. — It is a prominent fact that the blade ray of the 

 dermal hexactin and the distal ray of the gastral pentactin are very 

 long, compared with those of the specimens from Stations 4948 and 

 4876. This character seems to indicate some relation to the thick- 

 ness of the sponge body. The dermal hexactin has a very long blade 

 ray, measuring from 0.8 mm to 2.1 mm in length, while the hilt 

 ray and the guard ray are comparatively short, measuring llO/t to 

 187//, in length. 



I distinguish two forms of floricome, which I shall designate with 

 the letters a and h. They seem to represent different quantitative 

 proportions and to show certain differences in the manner of distribu- 

 tion within the sponge. Form a, the larger floricome, occurs com- 

 monly and measures 80/i to lOO/i in diameter. It has G to 9 terminals 

 (mostly 7) provided with 5 or 6 marginal teeth on the terminal 

 plate. It is abundant, both subdermally and at the apex of the 



