862 Rk. Etheridge, jun.—Carboniferous Tubicolar Annelida. 
is but a little pioneering. We will only so far anticipate as to say 
that there is nothing whatever in the thin beds at Lower Dunscombe 
alone, to warrant the supposition that they constitute a passage from 
Devonian into Carboniferous. 
VIL—A Conrrisvurion To THE STUDY OF THE BRITISH CARBONIFEROUS 
TuBicoLaR ANNELIDA. © 
By R. Eruerives, Jun., F.G.8., F.R.P.S.Edin. 
(Concluded from p. 307.) 
III. —Genus Serpula, Linneus, 1758. 
(Systema Nature, ed. 10, p. 786.) 
Obs.—As distinguished from Serpulites, the term Serpula is here 
made to include those tubes which were attached, or in all probability 
attached by some portion of their surface to other objects, and in 
which there is an absence of the thickened margins, and the posterior 
bifurcating shelly tubes of the former. The name can only be used 
in an approximate sense, for it is quite within the bounds of possi- 
bility that any of the species here referred to Serpula may be shown 
to have other affinities. Already two out of the limited number of 
British Carboniferous species have been so indicated. The fine rigid 
siliceous rods formerly called Serpula parallela, M‘Coy, are now 
known to be the anchoring fibres of a sponge allied to Hyalonema,' 
whilst it is more than probable that Serpula heaxicarinata, M‘Coy, is 
the corallum of a species of Heterophyllia. 
13.—Serpula indistincta, Fleming. (PI. VII. Figs. 80-82.) 
Dentalium indistinctum, Fleming, Edinb. Phil. Journ. 1825, xii. p. 241, t. 12, f. 2. 
Serpula compressa, J. de C. Sowerby, Min. Con. 1829, vi. p. 201, t. 598, f. 3 (non 
Eichwald). 
» 2 M‘Coy, Synop. Carb. Lime. Foss. Ireland, 1844, p. 168. 
5 5 Bronn, Index Pal. Nomen. 1848, p. 1136. 
Brown, Foss. Conch. 1849, p. 329, t. 98, f. 26. 
Serpulites compressus, Morris, Cat. Brit. Foss. 1854, ond ed. io. 93s 
Bigsby, Thes. Dev.-Carb. 1878, p. 243. 
(Compare Serpula subcincta, Portlock, Geol. Rept. Londonderry, 18438, p. 362.) 
Sp. char.—Tube thick, shelly, smooth, shining, slightly tortuous, 
or flexuous, somewhat compressed, tapering, not coiled upon itself, 
or in any way convoluted, or twisted. Section usually elliptical, at 
times approaching to the round. Surface smooth, or with indistinct 
annulations. 
Obs.—In 1825, the Rev. Dr. Fleming described, under the name 
of Dentalium indistinctum, an elongated, tapering, and somewhat 
curved tube, which, from its want a symmetry, it would be difficult 
to regard as a Dentalium. Dr. Fleming described this fossil thus: 
“Shell about two and a half inches long, and nearly half an inch in 
diameter. The surface when entire is smooth, dull, and of a whitish 
colour. It consists of several layers, the surfaces of which have a 
shining mother-of-pearl aspect . . . . In the limestone of the Coal 
formation of West Lothian.” 
He adds, “Specimens of this Dentalium were sent to the late 
' Prof. F. Roemer now places this in his genus Acestra (Lethea Geog. 1880. 
1 Th. 1st lief. p. 318). 
