304 R. Etheridge, jun.—Carboniferous Tubicolar Annelida. 
TJI.—A Conrripurion To Tur Stupy oF THE British CARBONIFEROUS 
TupicoLtakR ANNELIDA. 
By R. Erueriver, Jun., F.G.S., F.R.P.S.Edin. 
(Continued from p. 266.) 
9.—Spirorbis Dawsoni, sp. nov. (Plate VII. Figs. 26, 27.) 
Sp. char.—Tube small, sinistral, narrow, increasing but little in 
size towards the aperture, very narrow and fine towards the apex ; 
volutions not in the same plane, somewhat raised, with a sunken 
apex, rather deeply umbilicated on the attached side; section circular. 
Surface marked with faint, regular, equidistant, transverse ridges, 
which are more marked along the union of the whorls (or “suture ”) 
than on the periphery or back of the last volution. 
Obs.—This is one of the few sinistral species of Spirorbis we have 
in the British Carboniferous Limestone. Irrespective of this 
character, its small size, few volutions, and narrow vermiform tube 
will mark it as peculiar. It is otherwise distinguished from S. 
spinosa and S. caperatus by the style of the ornament, and from S. 
ambiguus by its less robust appearance and absence of the broad back 
of the latter species. Another character which appears to be peculiar 
to it is the prominence of the transverse ridges along the inner side 
of each volution. J have much pleasure in naming this after Dr. J. 
W. Dawson, who has been, in a great measure, instrumental in 
bringing to light the true history of these worm-tubes. 
Loc. and Horizon.—On the shore, opposite the ‘“ Vaults,” near 
Dunbar, in shale over the Vaults Limestone; on the shore to the 
east of Seafield Tower, near Kirkcaldy, in shale over the Seafield 
Sandstone, both horizons being in the Lower Carboniferous Lime- 
stone Group (Mr. J. Bennie). 
10.—Spirorbis (or Serpula?), sp. (Plate VIT. Fig. 28.) 
Obs.—I have met with a few fragments of free tubes, which 
appear to be characterized by very strong, and somewhat imbricating, 
accretion ridges, bearing a general resemblance to those seen in 
Serp. scalaris, M‘Coy,’ but much more numerous, and the tube very 
much smaller. 
Although the fragments are in no way sufficient for description, it 
is well to mention them in case more perfect specimens are in 
existence in private collections. They are distinct from S. Armstrongi. 
Loc. and Horizon.—Skateraw Quarry, near Dunbar, in shale above 
the limestone; Burlage Quarry, at a similar horizon (Mr. J. Bennie). 
I].—Genus Serpulites, Macleay, 1839. 
Serpulites, Macleay, in Murchison’s Sil. Syst. 1839, p. 700. 
ie ae Annals Nat. Hist. 1840, iv. p. 387. 
3 M‘Coy, Brit. Pal. Foss. 1851, fascic. 1. p. 182. 
Campylites, V Kichwald, Bull. Soc. Nat. Moscou, 1856, No. 2, p. 408. 
ss d’Kichwald, Lethzea Rossica, 1860, i. p. 675. 
Gen. char.—Tube smooth, arched, slightly calcareous, glossy:; 
having two small longitudinal tubes at opposite points of the 
1 M‘Coy, Carb. Foss. Ireland, 1844, p. 169, t. 23, fig. 29. 
