African Freshwater Sponges. 99 



Kacli is cncloseil in a thick coat of spongin. 'J'lie gemmule- 

 apicules lit- tanj^entiallv to tlie surface, aiul are cniln; lile<l in 

 this coat. Th« spicules are fairly numerous, hut are not 

 closely packetl to;;('thfr as in the allied species S. indica, 

 Annandale, S. anmatrana^ Wehor, an<l S. botnbni/ensin. Carter. 

 riuTe is a short foraniinal tuhtile which lies rather to one side 

 o( the pommule in its natural position. 



Spicules. — The rnacrosch'res are slij^htly curved, uniformly 

 niicrospineil strontryla. The ends are n little swcjUeii and 

 there is otton a slij;ht swelling; in the centre of the shaft. 

 The stioMi^yla measure 0*13-0*17 mm. in length by O'Ol- 

 0*015 mm. Amoni; them are scattered a few slender smooth 

 oxea with a well-marked swelling in the centre of the shaft. 

 These are nearly tho same length as the preceding spicules, 

 and are apparently young forms of the macroscleres, as they 

 lead on to thicker spicules which are oi)viously developing 

 macroscleres and which are nearly cylindrical, but some of 

 which still retain rather pointed ends. 



The free raicroscleres are slightly curved, sharply pointed, 

 microspined oxea measuring O'OG-OOl) mm. in length by 

 0*0025 mm. Some have a very feeble swelling at the centre 

 ot the shaft. 



The gemmule-spiculos are small, curved, sausage-shaped 

 spicules uniformly covered with minute spines. Sometinies 

 the ends are pointed instead of being rounded oft as is usually 

 the case. There is often a slight swelling in the centre of the 

 shaft. The spicules measure 0*035-0*06 mm. in length, with 

 a maximum diameter of 0*008 mm. 



Locality. Benguela j on a shell of .^Etheria elliptica^ var. 

 t uhifera. 



The subgenus Slratospongilla, Annaufhile (i), to which the 

 foregoing species belongs, is chiefly tropical in its distribution 

 {4). At the present day it is known to be represented in 

 India by three species — -S. bomhayensis^ Carter, S. indica, 

 Annandalc, and S. yraveUyi^ Annaudale; it occurs in Su- 

 matra — S. .<iumatratut, Weber ; in tropical and South Africa 

 — >). roufse/eti, Kirkpatrick, S. schubotzi, Weltner, varieties 

 of S. Huinatruna, Weber, and S. bombayensis^ Carter; in the 

 Fiji Islands — S. gilsoni, Topsent ; and in Eastern China — 

 S. sinensis^ xVnnaiidale. One species — S. dementis, Annan- 

 dale — from the rhilij)pines is doubituUy assigned to the 

 suligenus, and S. uavictlla^ Carter, from tho Kiver Amazon, 

 ajipt-ars to be an allied ft-rin. 



Of the foregoing species the following are most nearly 

 related to Spongilla bengueUnsisy sp. n. : — S. bombuyensis, 



7* 



