86 OKHAMANDAL MARINE ZOOLOGY REPORT PART IT 



5. Subdermal pseudosagittal triradiates (Figs. 8e, 8/). The form and arrange- 

 ment of these spicules strongly support the view 1 that they are really distal 

 tubar triradiates which have undergone rotation so that the original basal ray (&) 

 has come to lie in or below the dermal cortex, while one of the original oral 

 rays (o 1 ) has come to be directed inwards and has become more or less elongated. 

 I had previously looked upon this inwardly pointing ray as the basal ray of a 

 sagittal spicule, and upon the true basal ray as one of the orals. It will be well 

 in future to speak of the former (Figs. 8e, 8/, o 1 ) simply as the centripetal ray, 

 and the others as the outer or dermal rays. In the present case the dermal rays are 

 asymmetrical and it is quite easy to see which is the original basal ray (6), for 

 it is straight, while the other (o 2 ) is often more or less curved or crooked, and 

 really forms a pair with the centripetal ray, which is also frequently bent. The 

 centripetal rays usually lie in close juxtaposition with the centrifugal rays of the 

 subgastral sagittal triradiates. In a typical example the centripetal ray measured 

 about 0-13 by 0-01 mm., and the dermal rays about 0-11 by 0-01 mm., but the 

 centripetal ray may be more elongated. All the rays are more or less gradually 

 sharp-pointed. 



6. Colossal oxea of the dermal cortex (Fig. 8g). These spicules are fusiform 

 but commonly thicker at one end than at the other. They vary much in size, 

 up to about 2-85 by 0-075 mm. 



7. Hair-like oxea of the oscular fringe. Straight and very slender, only about 

 0-004 mm. in maximum diameter. Their length is probably about 0-6 mm., but 

 they are almost invariably broken short in preparations. 



Previously known Distribution. Port Elizabeth, South Africa (Bowerbank). 



Register Numbers and Localities. I., a number of good colonies from Okhamandal 

 Point (off Buoy ; 5. 1. 06) ; IV. 6, two small fragments from the S.W. Coast of Beyt 

 Island. 



4. Leucandra donnani Dendy, var. tenuiradiata nov. (Plate L, Figs. 4, 4a, 

 4b ; Plate II., Figs. 9o-9cZ). 



Leucandra donnani Dendy [1905]. 



There are five specimens in the collection which I think must certainly be referred 

 to this species, although the curious differences in the proportions of the spicules 

 make it desirable to give them a special varietal name. 



The external form in the best example (R.N. IV. 8, Fig. 4) agrees closely with 

 that of the type of the species from Ceylon, even in the curiously curved character 

 of the whole sponge. The colour, however, is white, owing to the absence of 

 the pigment granules found in the type. The brittle texture is pronounced and 

 has resulted in the breaking of the specimen in two. 



1 Cf. Dendy and Row [1913], p. 750. 



