THE SPONGES OF THE WEST-CENTRAL PACIFIC 



137 



194 p. There are abundant echinating acanthostyles, 4 p by 66 p to 6 p by 

 63 p. The microscleres are not common but do include distinctive palmate 

 isochelas, 10 p in length, with very narrow shovels and toxas about 40 p to 

 50 p. long. 



This species was first described as Raphidophlus cervicornis by Thiele, 

 1903, page 959, from the East Indian region. 



Thalysias cratita (Esper) de Laubenfels 



Text Figure No. 87 



This species is represented by the following : 

 U.S.N.M. No. 23029, My No. M. 408, collected July 30, 1949, by diver in 

 northwest Ponape, between the reef and the shore. The depth was 5 

 meters, and the substrate was dead coral. 



The shape is typically ramose, with branches 15 mm in diameter and 15 

 cm high. The exterior and interior color in life was pinkish red, and the 

 consistency was stiffly spongy. 



The surface is conulose, with conules, 3 mm high and 3 mm apart, hav- 

 ing rounded terminations. The pores and oscules are quickly closing. They 

 are not visible at the present time, nor is there any record of them in the 

 field. The surface is lipostomous. 



The ectosome is packed with spicules pointing in many directions but 

 chiefly towards the outside. The endosome has a reticulation of horny fibers, 

 and it also contains abundant spicules. 



The skeleton comprises, first of all, smooth styles which are inside or 

 coring the fibers, the latter being about 80 p in diameter. The styles are 6 p 



Text Figure No. 87. Spicules of Thalysias cratita, X 781. A and B: Two of the styles 

 from the fiber. C: One of the tylostyles as from between fibers, and as from the ecto- 

 some. D: Two of the echinating acanthostyles. E: Toxa. F: Palmate isochela, side and 



front views. 



