On a new Order of Echinoderms. 367 



the only genus of Echinoidea occurring in anything like a 

 corresponding relative abundance. So, if they are omitted from 

 these orders, they can only be referred to the Pentacrinite, which, 

 however, is rare. The microscopic structure is identical with 

 that of Pentacrinus ; and the rather concave form of the base 

 would agree with the rounded edge of a plate to which it might 

 be supposed they were attached. But if they are thus disposed 

 of, there will arise the question — what are Pedicellarise ? Are 

 they organs of the animal, or independent parasitical existences ? 

 If the former, it would appear extremely improbable, first, that 

 in the same genus the organs should so vary; and secondly, that 

 in those beds where Pentacrini abound, similar structures should 

 never have been met with. But then, on the other hand, sup- 

 posing them to be parasites, it is impossible to understand how, 

 in the recent state, specimens should never be found without 

 them ; and it also seems unlikely, as in the case of the Goniaster 

 alluded to, that the same species should have lived on from the 

 middle of the Cretaceous beds to the present day. By those 

 who believe the Pedicellarise to be a part of the animal on which 

 they occur, they are regarded as delicate organs of touch, or as 

 an apparatus for grasping. But it is very obvious that, in the 

 fossils in question, there is no trace whatever of that nipping 

 organization which distinguishes both the recent forms. In this 

 important structure the fossils certainly differ from Pedicellarise. 

 And then, one of the circumstances which have rendered the 

 determination of the nature of Pedicellarise so difficult is the 

 fact that there are in them no traces of vital organs ; but it can 

 scarcely be imagined that the deep slit in our specimens was not 

 formed for protecting some important organs, which, moreover, 

 are defended by the two rows of spines, and perhaps by the 

 angle of attachment, which is oblique, so that, were the organism 

 fixed, the slit would be turned somewhat downwards. It would 

 therefore seem evident that with the Pedicellarise they have no 

 relation whatever. With Pedicellarise the evidence is decidedly 

 strong in favour of their being organs of the animals on which 

 they occur ; with these the anatomical characters seem to be 

 unmistakeably those of independent existences ; and therefore it 

 cannot be necessary that they should occur on any animals in 

 particular. 



A further conclusion may now be deduced. It has been de- 

 monstrated that these fossils are not related to Pedicellarise, and 

 that they form no part of any member of the known orders of 

 Echinodetmata ; and it has also been shown that they possess 

 some of the most distinctive characters of Echinoderms ; there- 

 fore it will be evident that they are Echinoderms of a new type. 

 What that type is we will now endeavour to discover. 



