264 R. Etheridge, jun.—Carboniferous Tubicolar Annelida. 
In the Permian Spirorbis planorbites, Munster, the periphery 
appears to be somewhat crenulated by minute projections as shown 
in one of the figures of this species given by Geinitz,’ but this crenu- 
lation bears no comparison with that of S. Hichwaldi. 
Loe. and Horizon.—Quarry on bank of Linnhouse Water, opposite 
the Oakbank Oil Works, near Mid Calder, in a limestone of the 
Cement Stone Group (Calciferous Sandstone Series), associated with 
Sp. pusillus, and bivalves (Mr. J. Bennie). 
8.—Spirorbis Armstrongi, sp. nov. (Plate VII. Fig. 25.) 
Sp. char.—Tube planorbiform, dextral, the last turn large, and 
more or less covering the others. Surface spirally lined with 
microscopic striz, and crossed transversely at regular intervals by a 
series of sharp projecting ridges, crests, or frills. 
Obs.—This well-marked species has presented itself only in 
fragments, with the exception of one specimen, but, its appearance 
is so well marked that I think it deserves to be distinguished by a 
name. ‘The strong frills or crests which cross the surface of the shell, 
accompanied by the spiral fine strie, render this a conspicuous 
species. 
The nearest ally of S. Armstrongi, so far as I have been able to 
ascertain, is Spirorbis (Serpula) epithonia, Goldfuss,? which has 
similar transverse frills, but of a less degree, and no spiral striz, 
as in the present species. Next to this is Spirorbis laxus, Hall,® 
from the Lower Helderberg Group, but in this instance the 
ridges which cross the surface of the shell are mere annulations, and 
do not extend beyond the periphery, whereas in our S. Armstrongi 
the crests are sharp and erect, and in fact at times have an imbricat- 
ing appearance, as if representing successive growths of the tube 
which overlap one another. There is in this character, but in no 
other, a connexion with Serpula scalaris, M‘Coy,’ in which the same 
imbricating or overlapping of the successive growths of the tube is 
seen. 
Spirorbis angulatus, Hall,> is described as having the surface 
lamellose striate, the lamelle being crowded into ridges; without a 
figure it is difficult to say how far this would correspond with the 
present species ; it is however probable that it somewhat resembles it 
so far, although the “ upper angular side, sometimes nodose,” would 
at once separate them, as there is no trace of nodes in S. Armstrongi. 
I have much pleasure in associating with this species the name of 
Mr. J. Armstrong, whose researches in Carboniferous Paleontology 
are too well known to require comment from me. 
Loc. and Horizon.—Carlops Quarry, Peebles-shire, in shale over the 
Carlops Limestone, L. Carboniferous Limestone Group (Mr. J. 
Bennie). 
1 Dyas, t. 10, f. 10. 
? Petretacta Germaniz, t. 67 f. 1. 
° Pal. N. York, iii. t. 54, £. 18 a-e. 
* Synop. Carb. Lime. Foss. Ireland, t. 23, f. 29. 
® Fifteenth Ann. Report State Cab. Nat. Hist. N. York, 1862, p. 112. 
