132 Mr. H. J. Carter on Fossil Sjjonge-spicules of 



specimens, but differs from the bihamates of sponges generally 

 in being caleareous instead of siliceous, more or less crooked, 

 and provided with a little point in the middle of its convex 

 side, by which, as is wont with these spicules, it is attached to 

 the flesh of the echinoderm. I need hardly add that the spi- 

 cules of the Spongiadse are free. 



Next come figs. 46 and 47, which are as abundant in the 

 Haldon deposit as they are remarkable for their beauty : these 

 are moniliform, cylindrical, slightly diminishing towards the 

 end, and slightly curved ; they vary in thickness and in the 

 number of their moniliform. inflations, which seldom exceeds 

 eight ; but in fig. 46 there are nine, the end one of which 

 on one side, having been apparently broken off, has been re- 

 stored. Fig. 47 is another form of the same spicule, which is 

 thicker, more obtuse at the ends, and has only six moniliform 

 inflations : they vary somewhat in size also, and many are 

 fragmental ; but the more perfect form seems to be that of fig, 

 46. I know of no sponge possessing spicules like these ; at 

 the same time, being so abundant, and remarkable for their 

 beauty and the peculiarity of their form, they demand specific 

 distinction. Hence we will call this spicule MoiiiUtes haldo- 

 nensis. 



Fig. 54 appears to be an eroded state of the same spicule, 

 unless it was one like that figured by Dr. Bowerbank (Brit. 

 Spong. pi. 11. fig. 244). 



Again, there is another moniliform spicule, much smaller 

 than the foregoing, which is represented in figs. 44 and 45. 

 This, however, is not linear like the last, but apparently 

 quadriradiate. I say " apparently," because I am not quite 

 certain that in some instances one ray Avould not be found to 

 be longer than the rest, in which case it would belong 

 to the ternate-shafted spicule represented in fig. 71. All its 

 rays are moniliform, straight, and pointed, with such sym- 

 metry as to make it, although very small, a beautiful object. 

 I also know of no existing sponge that possesses a spicule 

 like this, for which I propose the name of Monilites quadri- 

 radiatus. 



Fig. 47 is a very common form in this deposit, about the 

 same size as Monilites hcddonensis^ but differing from it chiefly 

 in being smooth instead of moniliform. It varies much in 

 thickness and a little in length below that of the figure ; but 

 possessing no peculiarity referable to any existing sponge, no 

 further notice of it is necessary, except that it is remarkable 

 for its multiplicity, and originally may have formed the 

 smaller S])icule of one of the Coralliospongiaj, as a similar 

 spicule, although a little less in size than the one figured. 



