252 Mr. II. J. Carter on Sponge- Spicules from 



anckorata, which, in amorphous fragments, exist inside the 

 tubes of the Farrea and on the surface of the Corticium re- 

 spectively. 



Lastly, we come to two beautiful forms of sponge-spicules 

 which were found free in an arenaceous deposit of the Agulhas 

 Shoal at the Cape of Good Hope, and in the neighbourhood 

 of Colon, Panama, respectively : — the former dredged up by 

 Dr. G. C. Wallich himself in 1857 ; and the latter from Colon, 

 together with the forcipiform spicule above mentioned, just 

 mounted and forwarded to me by Mr. F. Kitton, of Norwich. 



For the sponge bearing the spicule from the Agulhas Shoal I 

 propose the name of " Gummina WalUchn" and for that from 

 Colon " Corticium Kittonii." 



To some it may seem strange to give a name to a sponge 

 from a single form of spicule ; but when it is considered that 

 there is no kind of sponges but the Gummineas of Schmidt 

 in which such-like spicules are to be found, and that the 

 spicules themselves respectively are sufficiently remarkable 

 to characterize any sponge, the difficulty will probably dis- 

 appear. Let us now proceed to their description, beginning 

 with 



Gummina WaUtchti, n. sp. PI. XV. fig. 46, a, b, c. 



Spicule acerate, curved, fusiform, covered with twelve (?) rows 

 of prominent tubercles, alternately placed in longitudinal lines 

 extending from one end of the spicule to the other (fig. 46, b). 

 Tubercle (fig. 46, c) consisting of a short cylindrical process 

 somewhat expanded at the base, constricted in the centre, and 

 again slightly expanded at the summit, which is round (fig. 

 46, c). Central canal (fig. 46, a) bent angularly in the centre, 

 from which it proceeds towards each extremity in a slightly 

 undulating form, straightening towards the end. Size of spe- 

 cimen 58 by 4£-1800ths inch in its greatest diameters. 



Obs. Of the arenaceous deposit in which this exquisitely 

 beautiful spicule was found, Dr. G. C. Wallich, who kindly 

 sent it to me in February 1871, states, " I have a considerable 

 quantity of a green sand-like deposit which I dredged up in 

 80 to 100 fathoms water on the Agulhas Shoal so long ago as 

 1857." 



It is interesting to find that the arenaceous deposit from 

 which Mr. Kitton obtained his spicules was of a like nature, 

 inasmuch as, after boiling a portion of it in nitric acid, he 

 states that the casts of the internal cavities of Foraminifera, 

 minute corals, and boring sponges, which were also present, 

 came out of a " dark green colour like the greensand fossils." 



