452 THE CANADIAN NATURALIST. [DeC. 



in favour of the conclusion that the openini^ in the vault of these 

 Crinoids is the mouth. 



But, if they were not in the habit of eating these Mollusks, it 

 may be asked what could have been the nature of the relations 

 between the two, that so frequently brought them together as we 

 now find them ? The first explanation that suggests itself is, 

 that possibly the Mollusk may have been preying upon the 

 Crinoid. But the fact, already stated, that these Mollusks 

 evidently lived long enough attached to these Crinoids, as we 

 have every reason to believe, during the life of the latter, to have 

 at least increased the size of their shells considerably, if not 

 indeed during their entire growth, is alone an almost insurmount- 

 able objection to such a conclusion. Doubtless, like other 

 marine sedemary animals, these Molluscs, when very young, 

 floated freely about in the sea, until they found a suitable station 

 to attach themselves, where they remained during life. May 

 they not, therefore, have been attracted to the bodies of Crinoids 

 by the numerous little organisms brought in by the action of cilia, 

 along the ambulacral furrows of the arms of the Crinoids, or in 

 currents produced by the motions of the arms of the latter? 

 The excrementious matter of the Crinoid could doubtless have 

 passed out under the foot of the Platyceras, supposing the 

 opening in the Crinoid sometime^ covered by these shells to have 

 been the anus, but it is diSicult to conceive how food could have 

 passed in, if we suppose this opening to be the mouth. 



ON THE EXISTENCE OF ROCKS CONTAINING 

 ORGANIC SUBSTANCES IN THE FUNDAMEN- 

 TAL GNEISS OF SWEDEN. 



By Mes.srs. Igelstrou, ISTordenskiold, and Ekman.* 



1. On the Occurrence op Thick Beds of Bituminous 

 Gneiss and Mica-Schist in the Nullaberg, Parish op 

 OsTMARK, Province op Wermland, in Sweden. 



By L. I. Igelstrom. 

 The parish of Ostmark, as well as other parts of western 

 and northern Wermland, is filled with high and steep hills of 



* Reprinted from communications read to tbe Royal Swedish 

 Aeudemy of Sciences at Stockholm. 



