346 On the Sti'omatoporoids and Eozoon. 



channels between chambers and in the cliambers themselves, 

 {. e. in the spaces formerly filleJ with sarcoJe. Similar 

 structure to the above is found in the recent Perforate Fora- 

 minifera. Weathered edges of specimens of Eozoon are finely 

 laminate. 



With regard to Eozoon, two objections are urged against 

 the organic theory, viz. the immense antiquity of the Lower 

 Laurentian limestones and the unlikelihood that any organic 

 structure could survive the effect of metamorphosing agencies. 

 Concerning the first objection, it may be said that when once 

 an organism is entombed and infiltrated the time factor j;)er se 

 is not an important one. Many Devonian Stromatoporoids 

 are less well preserved than those of Silurian age, and a 

 Foraminiferan might retain its structure as well in a Lauren- 

 tian as in a Wenlock limestone. The effect of igneous action 

 on the fossils of any particular formation is apparently more 

 or less a matter of chance, and examples of late origin may 

 fare worse than those of earlier date. 



Leaving hypotheses and coming to facts — to wit, the speci- 

 mens themselves, — I find that the Foraminiferal theory is 

 wholly adequate, and I am certain it is unnecessary to go 

 further afield in search of some highly complicated and proble- 

 matical theory of mineral origin. As a matter of course, the 

 evidence for the mineral theory, based mainly on the existence 

 in Eozoon of minerals of igneous origin, falls to the ground in 

 presence of the least trace of indubitable organic structure. 



Summary. — The Stromatoporoids are Foraminifera. 

 Eozoon canadense likewise belongs to the Foraminifera, 

 and is nearly related to Labechia and Beatricea, 



Note on Caunopora. 



Many of the Caunopora tubes so f lequently found in Stroma- 

 toporoids are not corals, but Chfetopod worms, apparently 

 belonging to the group Spioniformia. 



It is sometimes possible to see anatomical features, such as 

 the introvert, pharynx, intestine, peristomial cirri, and acicula. 

 The supposed " tabulre," which have misled some investi- 

 gators, are simply the expression of Annelidan segmentation 

 or, rather, annulalion. 



I have found what appears to be a similar kind of worm 

 in the living MonticuUpora {MerVui) normani, and at Porto 

 Santo Island have often watched it extending and drawing 

 in its peristomial cirri or " tentacles." The Palaeozoic Monti- 

 culiporasare frequently infested with a worm possibly related 

 to this modern one. If this is so, we liave a curious instance 

 of the conservatism of Nature. 



