256 VERMES SUB-KINGDOM IV 
obscure remains have been described from the older Palaeozoic formations. 
The burrows have the form of straight or tortuous tunnels, and are sometimes 
hollow, but more commonly have been filled up by the matrix of the rock. 
Various names have been applied 
to them, such as Scolithus, Areni- 
cola, Histioderma, Planolites, Diplo- 
craterion, Spirocolex, Scolecoderma, 
etc., but they are obviously in- 
capable of precise determination. 
Similarly, the serpentine or 
vermiform impressions known 
as Nereites, consisting usually of 
a number of windings, and often 
of profuse occurrence in various 
Palaeozoic formations, were 
until quite recently regarded as 
worm-tubes, or markings made 
by Fucoids. These also have 
: ” received numerous appellations, 
Fic. 410. such as Nereites (Fig. 409), 

Crossopodia (Crossochorda) scotica, M‘Coy. Ordovician ; Nemertites Myrianites Nemapodia 
Bagnoles, Normandy. - Atle ae Z s 2 
Crossopodia (Fig. 410), Phyllodo- 
cites, Naites, etc. Nathorst, however, has brought forward experimental 
evidence to demonstrate that the majority of these markings have been pro- 
duced by the movements of Crustaceans, Annelides, and Gastropods. A 
like origin may be reasonably ascribed to the extraordinarily abundant and 
variable vermiform structures known as “ Hieroglyphics,” which occur in the 
Flysch, Carpathian Sandstone, and in the marine facies of the Cretaceous and 
Jurassic formations. 
