CONODONTS IN ARENIG-LLANDEILO FORMATIONS. 243 



of a toothed plate of equilateral syniuietry. If Couodonts 

 belonged to odontopliores, we ought to find, I think, two of the 

 former to one of the latter; but this is just what we do not 

 find, as amongst all the specimens collected by me from the 

 Arenig-Llandeilo chert-shales, and from the other shales men- 

 tioned, only one or two might be referred to the central row 

 of an odontophore. From this little bit of negative evidence 

 I think I am justified in rejecting the odontophore theory. 



On searching the chert-shales I kept a sharp look-out to see 

 if I could find any remains of tracks on the shales, but saw 

 none, so that the Conodonts in all probability belonged to 

 animals which were pelagic, or at least did not move on the 

 bottom of the ocean. 



I am inclined to agree with Pander, of Russia, in his original 

 suggestion that Couodonts are the teeth of primitive fishes. 

 The animals to which they belonged — whether fishes or not — 

 appear to have had no other hard parts. This could not be 

 made out from the Carboniferous specimens I collected,* owing 

 to the fact that a large quantity of the debris of small fishes 

 is got with them; but in the Arenig-Llandeilo rocks of the 

 Southern Uplands of Scotland they occur with only an occasional 

 annelid jaw, and no other fossils likely to be taken for fish. 

 Why they should be abundant in one bed of cherts-shale and be 

 all but absent from another is hard to understand. 



In the Arenig-Llandeilo strata we may expect to find a great 

 variety of Conodonts, for the animals to which they belonged 

 appear to have had the waters of the old oceans of those times 

 pretty much to themselves, and must have been in great 

 abundance when some of the beds were being deposited. 



Conodonts were discovered by Pander in the Cambro-Silurian 

 rocks of the Baltic Provinces of Russia, and figured in his 

 Monograph in 1856. 



In 1878 I exhibited to this Society a large number of Cono- 

 donts collected by me from the Carboniferous strata of Scotland, 

 but at that time no Scotch naturalist knew anything about them. 



In 1879 Dr. G. Jennings Hiude gave a short history of 



* Trans. Nat. Hist. Soc. Olas., Vol. V. (N.S.), 1898-99. 



