ANNELIDA. 



323 



sinuously folded, and Been in horizontal section. In fig. 192, 

 c, a portion of one of- the specimens referred to is figured, 

 from which it will be seen that the fossil cuts directly across 

 the lamince of deposition, its actual surface (where exposed by 

 exfoliation of a part of the slab) being marked with concen- 

 tric striae. It is therefore quite clear that Myrianites was 

 really a thin erect, folded, leaf-like expansion, of some kind 

 or another, and that what palaeontologists have described 

 under this name is only the horizontally-cut edge of this 

 expansion as seen on the surface of the stratum. What 

 Myrianites really is, is quite an open question. It is, per- 

 haps, a peculiar form of Fucoid. That it is not Annelidan 

 seems perfectly certain. 



Another fossil which has generally been regarded as refer- 

 able to the Errant Annelides is the Crossopodia of M'Coy 

 (fig. 193), also very abundant in certain Silurian strata. In 



Fig. 103. Crossopodia Scotica, a supposed Aimelide track. Silurian. (After M'Coy.) 



this fossil there is a central narrow groove, which winds in 

 serpentine bends over the surface of the stone, and is sup- 

 posed to represent the body of the animal, bounded on each 

 side by a broader and generally ill-defined space, supposed 

 to represent the foot-tubercles. That Crossopodia, however, 

 should be the petrified body of an Errant Annelide seems 

 almost incredible, and that it is even the track of one of 

 these creatures is extremely improbable. In well-preserved 



