Pl,ATYC'RINID.i:. PLATYCUINITES. 1 5 



admixture of species must be coiisideicd as exceptions to the general law by which each 

 species was contiiied to the peculiar locality best suited to its habits, and in which it was 

 destined to live. It is no doubt true that in sonic localities crinoidal remains are mixed 

 promiscuously together ; but wlien this is the case, they have been mostly washed into 

 the position they occupy in the strata by the currents which prevailed at the period of 

 their deposition, and which swept them from the spots on which they originally 

 flourished. This is frequently evident from the absence of the more delicate organs of 

 those animals which have been exposed to the action of water, as well as by the worn 

 appearance of their less perishable parts. 



The P. Itevis must lia^e been abundantly, though probably not generally, diffused in 

 the seas of the carboniferous epoch, for its remains are numerous in the locahties 

 enumerated in a preceding page, more so perhaps in that portion of the mountain lime- 

 stone formation which is so largely and beautifully developed in Ireland than at other 

 points. When the same formation which presents such an extensive field for research 

 in Russia shall have been carefully examined, it is not improbable that this and other 

 sijecies will be found equally abundant there as in the British Isles. Shoidd tliis con- 

 jecture not pi-ove correct, the horizontal range of the species must have been confined 

 ■vAdthin rather narrow limits, as compared with the extent of the ancient sea of which it 

 was a denizen. 



Goldfiiss and other continental writers have represented the Plati/crinites Icevis as 

 occuiTuig in the transition, or primary fossiliferous strata of Germany. The only 

 e\ddence in support of this conclusion is that of a few fi-agmentary portions of elMptical 

 columns. But as that form of column is not confined to a single species, these disjointed 

 fragments are not sufficiently specific to warrant the conclusion that they appertain to 

 the P. lo'vis. They may Avith greater probability be referred to the P. deprcssus, P. 

 ventricofufs, or some hitherto imdescribcd species. 



No indication of the P. lavis has hitherto been discovered in the carboniferoiis strata 

 of Yorksliire. Mr. Phillips has, however, in his Geology of that county, figured a 

 Platycrinite as the lavis, but which is really a different species. 



It has been impossible to detemiine whether the P. IcEvis possessed an anus or not, 

 as the part where it wordd be natiu-aUy looked for, the plated integument above the 

 rays, is generally so covered ^ith the tentacula, that no satisfactory evidence on the 

 point can bo obtained. 



Base of attachment. — Though this portion of the animal has never been discoA'ered, 

 there can be no doubt that all the species of Platycrinites were permanentl)- fixed to the 

 bed of the ocean. This we infer from the length and form of the column, which would 

 have been a hea%^ encumbrance to an animal capable of locomotion. But if it was 

 attached, then the greater the length of the column the more power it must have 

 possessed of procuring its subsistence. 



