234 



THE SPONGES OF THE WEST-CENTRAL PACIFIC 



Tethya actinia de Laubenfels 



Text Figure No. 161 

 Plate XI, Figure c 



This species is here represented by the following : 



U.S.N.M. No. 22977, My No. M. 353, collected July 5, 1949, by diver from 

 the Pearl Pool at the west end of the lagoon at Ebon Atoll. The depth 

 was 5 meters, and the substrate was dead coral. This species was mod- 

 erately common throughout the lagoon of Ebon Atoll. 



U.S.N.M. No. 22820, My No. N. 027, collected August 17, 1949, by F. M. 

 Bayer on the outer reef near Bikini Islet at Bikini Atoll. 



This species is spherical and about 2 cm in diameter. 



The color in life was brilliant red, becoming nearly white upon being 

 immersed in alcohol. The endosome was deep orange, and the consistency 

 was cartilaginous. 



The surface is tuberculate, as in all species of Tethya, with tubercles 

 about 2 mm in diameter and upwards of 1 mm high. Some of these at Ebon 

 had long projections (incipient buds), which indicates an approaching re- 

 productive cycle. The pores and oscules cannot be made out, because they 

 close in the process of collection. 



The ectosome is corticate, about 1 mm thick; and the endosome is pro- 

 nouncedly radiate. 



The skeleton comprises megascleres which are practically styles, being 

 fairly sharply pointed at one end. This is somewhat unusual in the genus 



B 



A Q 



) 



Text Figure No. 161. Spicules of Tethya actinia. A: Style, X 182; the entire spicule 

 shows, but in two parts. B: Smaller style, X 182. C: Spheraster, X 782. D: Tylasters, 

 X 782. E: Oxyeuaster with forked rays, X 782. F: Greatly modified oxyaster with 



forked rays, X 782. 



