African Freshwater Sponye». 07 



scnltercd over part.^ ot" the shell now A'w.a from tli<! sponfrc. 

 They are (irmly jiltuehcil to t!io ftiii-II and r(f.-t dm n dfiirtc 

 mass ot' L'ommnle-spieules. 



Spicules. — The nmcrosclero? aro sliujiitly curved, stout, 

 smooth oxen, tnporing ahruptly at each end to a sraall sharp 

 poijit itito which the axinl canal oxtend.s. The spicule.^ are 

 8li<;hllv swolh'u at the endn, and sometimes there is a faintly 

 niarktd swelling at the centre oi the shaft. Tiiere aro U(jt 

 many ahnormal forma present, hut some of the spicules are 

 irregularly bent and occasionally ono end is rounded off. 

 More randy hoth entls are rounded. The niacroscleres 

 measure 0'27.')-03155 mm. in letigth and have a thickness 

 of 0"02-0*027 inm. Tliey resemble in some degree the more 

 pointed macroscleres of SpoivjiUa crassissima, Aninmdale, 

 var. crassior, Annandale, but they are more swollen at the 

 ends and aro somewhat longer and tiiicker. 



There are no free mieroscleres present in the sponge. 



The gemniule-spiculrs are short, thick strongyla |)rovided 

 "Nvilh strong spines. Some of the spicules, especially the 

 shorter ones, are swollen in the middle, so tiiat they are 

 barrel-shaped ; others are nearly spherical, but still bear a 

 few spines. The spines are p;rou[»ed at either end of the 

 strongyla, leaving the centre u£ the shaft smooth, but often a 

 few scattered spines occur along the shaft. The spines are 

 stout ; tvpically they are strongly curved towards the centio 

 of the shaft and end in a sharp point; but many of them are 

 »t'>uf, straight, knob-like projections. The spicules nita-uro 

 fiom O'OlJa-Ul mm. in length and have a thickness of 0"()12- 

 0i)16 mm. Some of the short inflated ones are as much as 

 0'U2l mm. in diameter. 



Localifi/. Benguela ; on a shell of ^theria ellipti'ca, var. 

 tuhi/era. 



Spongilla (Strafospongilla) benguelensis, sp. n, 



Tlie sponge occurs in a number of very small patches 

 towards the edges of the lower valve of the ^Etheria shell on 

 which the previously described species is growing. Tiiere 

 are the femains of various other patches of the sponge also on 

 the lower valve in the region of the hinge and one or two 

 minute sp»)cimens on the upper valve. These patches of 

 sponge are very inconspicuous, as they run chietly in the 

 furrows of the siiell ; in the dried state they are soft to the 

 touch and their surface is even. Scattered over parts of the 

 lower valve of the shell are fpiite a number of gemmulos 

 belonging to this 8()ecie8. Each geiumulo is lirmly tixod to 



A fit. ii: Mug. y. I list. b5.r. 9. I W. ill. 7 



