72 CEYLON PEARL OYSTER REPORT. 



Myriastra clavosa (Ridley). 



1884, Stelletta clavosa, Ridley (16); 1888, Myriastra clavosa, Sollas (15). 



I have no hesitation in referring to this species four small specimens from deep 

 water off Galle. The sjjecimens are approximately spherical in form and up to about 



9 millims. in diameter. There is a single slightly depressed vent, which, in three of 

 the specimens at any rate, has a membranous margin. The colour is grey-yellow. 

 As this is an entirely new locality for the species, which has hitherto been obtained 

 from waters north of Australia, I propose to give the details of spiculation of one 

 specimen in justification of the identification. 



Spicules. (1.) Dichotrifenes ; shaft, 1'4 millim. by 0'025 millim., gradually and 

 finely pointed; chord, 0'6 millim. ; protocladi, 0'08 millim. ; deuterocladi, 0'2 millim. 



(2.) Anatriasnes ; shaft, 2 - 3 millims. by 002 millim., very finely and gradually 

 pointed; chord, 0"1 millim.; cladi, 0"0f> millim., rather stout; of the shape figured 

 by Ridley. 



(3.) Large oxea ; fusiform, gradually and sharply pointed, 2"2 millims. by - 025 

 millim. 



(4.) Cloacal oxea; commonly 0"2 millim. by 0'004 millim., may be rather larger. 



(5.) Chiasters ; extremely minute, with no distinct centrum, and long, slender, 

 tylote rays varying in number; total diameter, 0*01 millim. 



It will be seen from the above that the shaft of the dichotrisene is a good deal 

 shorter than in previously described specimens, but, considering the variation in this 

 respect, we cannot regard this difference as being of specific importance. 



R.N. 131, 132, 227, 228 (all from off Galle and onwards up the West Coast of 

 Ceylon, depths up to 100 fathoms). 



Myriastra tethyopsis (Carter). 



1880, Stelletta tethyopsis, Carter (4) ; 1888, Myriastra (?) or Anthastra (?) tethyopsis, 

 Sollas (15). 



There are four specimens of this very remarkable sponge in the collection. Sollas 

 regards the species as insufficiently characterised, but, as a matter of fact, Carter's 

 description is very good, and leaves no doubt as to the identification. The fact that 

 Sollas was unable to assign it definitely to any of his genera tends rather to show 

 the unsatisfactory nature of his system of classification than the insufficiency of the 

 original description. 



The specimens (in spirit) are light grey in colour. The smallest is about 



10 millims. and the largest about 42 millims. iii diameter. The shape is very 

 characteristically turbinate, more or less flattened below, and conical above. The 

 surface is harsh to the touch and finely granular, very minutely and rather sparsely 

 hispid. In the larger specimens a dense mass of long, hair-like spicules projects from 

 more or less of the lower surface. The larger specimens were evidently attached 



