114 



of the spicula on the surface. When treated with caustic potash., 

 the internal network is destroyed, leaving only the external spicula 

 placed side by side. 



This genus is allied to Grantia, but it is easily distinguished by 

 the uniform fusiform shape and the disposition of the spicula. 



Aphroceras alcicornis. (PI. X.) 



Hab. Hong-Kong (Dr. Harland). 



This species somewhat resembles Grantia botrxjoides in appear- 

 ance and habit; but in that species the spicula are all triradiate, 

 which appears to be the generic character of the genus Grantia as 

 I propose to restrict it. 



0'. On Aphrocallistes, a New Genus of Spongiad^e from 

 Malacca. By Dr. John Edward Gray, F.R.S., V.P.Z.S., 

 President Ent. Soc. 



(Radiata, PI. XL) 



In 1842 we received from Captain Sir Edward Belcher a Sponge 

 which he obtained in Malacca, which evidently forms a new genus 

 nearly allied to the Euplectella of Professor Owen. I therefore have 

 great pleasure in bringing a description of it before the Society. 



Aphrocallistes. 



The sponge cylindrical, tubular, branched ; the end of the main 

 tube closed with an open network formed of spicula ; branches 

 cylindrical, simple, rarely bifid, rounded and closed at the end ; the 

 inner surface of the tube with large unequal-sized concavities placed 

 in longitudinal series, having a large roundish oscule near its lower 

 edge. 



The sponge hard, calcareous, with uniform, close, equal, regular 

 hexangular pores on the surface, and larger round ostioles in series 

 on the sides of the main tube. The outer surface formed of inter- 

 tangled transparent spines, which inosculate and unite with each 

 other at the intersection, forming a hard, rather brittle crust. The 

 inner surface lined with a coat of fusiform transparent spicula, which 

 are placed in bungles parallel to each other in the spaces between 

 the roundish internal apertures of the crowded small superficial 

 pores. 



This genus is very like Euplectella of Professor Owen in its ex- 

 ternal form, and especially in the upper part of the tube being closed 

 with network. 



It differs from that genus in being more irregularly formed and 

 branched, and in the structure and calcareous composition of the 

 sponge itself. 



In that genus the basis of the tube is formed of ropes of elongated 

 spicula placed at right angles longitudinally and transversely to the 





