132 Mr. H. J. Carter on Fossil Sponge-spicales of 



specimens, but differs from tlie biliamates of sponges generally 

 in being calcareous 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 Spongiadaj are free. 



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

 llaldon 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, ha\ang 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 2IoniUtes halclo- 

 nensis. 



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

 unless it was one like that figm-ed 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 would not be foimd to 

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

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

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

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

 I also know of no existing sponge that possesses a spicule 

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

 radiatus. 



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

 same size as MoniUtes lialdonensis ^ 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 Coralliosjjongias, as a similar 

 spicule, although a little less in size than the one figiu'cd. 



