322 



DISCOVERY REPORTS 



1-5 mm. The chelae are rare in the second specimen and do not exceed o-oo6 mm. in 

 length, and are apparently absent in the first. The toxa in both range from 07 to 0-07 mm. 

 long, the larger being o-oo6 mm. thick and strongly spined at the ends. 



In spite of the differences from the holotype, I have little hesitation in identifying 

 these two specimens with Thiele's species. The diff'erences in the external form are 

 comparatively unimportant, and the difl'^erences in the measurements of the spicules are 

 no greater than those found in the various specimens assigned to O. thielei (see below), 

 a closely related species. Regarding the toxa, it is of interest to note that in O. thielei the 

 large toxa are often rare and difficult to find, and it is possible that large toxa are present 

 in the holotype of O. membranacea but in such small quantities as to be readily over- 

 looked. Even if they are actually absent, in view of the observations made on O. thielei 

 I should still feel justified in identifying the two present specimens with Thiele's species. 



Table showing dimensions of spicules in O. membranacea. 



The measurements of the spicules, which are averages, are given in mm. 



Distribution. Juan Fernandez. 



Ophlitaspongia thielei, sp.n. (Plate LV, fig. 8; Fig. 32). 



Holotype. B.M. 28. 2. 15. 219. 



Occurrence. St. 42: South Georgia, 120-20401.; St. 148: South Georgia, 132-148111.; St. 156: 

 South Georgia, 200-236 m.; St. WS 25: South Georgia, 18-27 "^• 



Diagnosis. Sponge massive; surface hispid and produced into papillate processes or 

 meandrine ridges which may be so strongly developed as to give a clathrate appearance, 

 or may be reduced to a feeble furrowing; pores apparently small and simple, and 

 scattered evenly throughout dermis ; oscules circular, 1-2 mm. in diameter, with delicate 

 membranous velum, leading into cavernous sub-dermal crypts ; often there is a single 



