1908.] 



AFRICAN CALCAREOUS SPONGES. 



441 



Most species of Leucosolenia contain triradiates as well as 

 quaclriradiates, and the facial rays of both soi'ts of spicule are 

 usually alate and regularly placed with the basal i-ay downwards. 



Text-fiir. 



Leucosolenia irregularis. X 2. 



Text-fig. 89. 



Leucosolenia irregularis, skeleton of dermis. X 150. 



All the spicules in the new species are large, two or three 

 times the size of those in the British species of Leucosolenia. 

 The facial rays of the larger quadriradiates are usually of the 



