212 



that of the other species, I shall now proceed to the inquiry respect- 

 ino- its inferior extremity, or organ of attachment. 



In the same spot where the fossil already described has been so fre- 

 quently found, at Bradford, small protuberant masses, of a peculiar 

 nature and form, have for some time been noticed on the surface of 

 the limestone. These masses are evidently of a spathose nature, and 

 their colour is remarkable, being a very dark grey, with so much of 

 a purplish hue, as to have very much the appearance of the purple 

 fluate of lime. 



Having obtained, in addition to those which I already possessed, 

 several very illustrative specimens from the Rev. Mr. Townsend, and 

 having purchased several others from different collectors in the neigh- 

 bourhood of Bath and Bristol, I proceeded to their examination. 



Rubbing several of these masses down in different directions, and 

 giving to them the necessary polish, their real nature and their peculi- 

 arity of structure became manifest, Plate XVI. Fig. 5, 12, and 14. 

 That they were formed of a continuation of the entrochal column 

 of this species of animal was rendered obvious, by several of the spe- 

 cimens ; the same peculiar neatness in the general form of the co- 

 lumn, as well as in its crenated articulations, being observable in 

 these, as has been already noticed in the column, Plate XVI. Fig. 1. 

 But if a doubt existed as to the identity of the species to which these 

 several parts belonged, it must be removed by the examination of 

 the column, Plate XVI. Fig. 5, which, with all the properties ob- 

 servable in the preceding column, possesses the particular characters 

 of that substance which is found adherent to the limestone rock, and 

 which may be considered as the pedicle or radicle of this species, 

 and as answering to the astropodium of Lhwydd, and to the radii 

 stellarum polyactinobolorum of Rosinus. 



In this specimen the same circumstance is observable, on which it 

 was found necessary to dwell so particularly, whilst examining the 



