R. ETHERIDGE, JUN., ON LO WEE-CARBONIFEROUS INVERTEBRATE. 9 



Class ANNELIDA. 

 Order Tubicola. 



Genus Spirorbis, Lamarck. 



Spirorbis, Lamarck, 1818, Hist. Nat. Anim. sans Yertebres, v. 

 p. 358. 



Spirorbis carbonarius, Murchison. PL I. figs. 1 & 2. 



Microconchus carbonarius, Murch. Sil. Syst. 1839, p. 84, f. D 1-10. 



Spirorbis carbonarius, Murch. Siluria, 1867, 4th ed. p. 302, Foss. 

 83. 



Sp. char. Tube attached by one side, forming a more or less 

 closed helix of from 1| to 3 turns, not all in the same plane, in- 

 creasing in size slowly towards the aperture, and dextral ; umbilicus 

 deep ; aperture oval or circular, sometimes extended into a short 

 free tube. Ornamentation consisting of unequal ridges of growth, 

 with intervening microscopic spiral striae. 



Obs. This is so variable a species that I have been able to dis- 

 tinguish no less than four, or perhaps five, well-marked varieties 

 in a large collection of specimens which has lately passed through 

 my hands, besides Mr. Henderson's specimens. The above descrip- 

 tion applies only to the latter, and would require to be somewhat 

 extended to include the varieties. Another point to be determined 

 is the relation this species bears to Spiroglyphus marginatus, M'Coy, 

 as it frequently forms a distinct groove for itself on the organism to 

 which it is attached. 



Loc. and Horizon. In black bituminous shale at Katesmill, above 

 Colinton, Water of Leith, associated with Anthracomyascotica, R. 

 Eth., Jun. In entomostracan shale, adhering to indeterminable 

 bivalve shells at Woodhall, Water of Leith. Both horizons in the 

 Wardie-Shale division of the Cement-stone group. 



Genus Serpulites, Macleay. 

 Serpulites, Macleay, 1839, Murchison's Silurian System, p. 700. 



Serpulites carbonarius, M'Coy. PL I. fig. 3. 



Serpulites carbonarius, M'Coy, Synop. Carb. Eoss. Ireland, 1844, 

 p. 170, t. 23. f. 32. 



Sp. char. Tube small, compressed, shelly, terminating posteriorly 

 in two lengthened cylindrical tubes, the prolongation of the lateral 

 thickened ridges (M i Coy). 



Obs. The posterior cylindrical tubes are not preserved ; but the 

 lateral thickened ridges are quite clear. Prof. M'Coy describes the 

 tube as shelly ; but I am satisfied that a certain amount of horny 

 matter also entered into its composition. The longitudinal wrinkles 

 on the surface of the tube are sufficiently fine to pass for striae. 



Loc. and Horizon. In a bed of marine shale, below the ford at the 



