SPIRORBIS GRANULATUS. 401 
from base to apex, and end in a somewhat long non-ciliated process, which in life 
projects beyond the pinne, though in the preparations it 1s obscured by these. Filaments 
are pinkish, except at the tip, and have a strong band of muscular fibres at the base of the 
richly ciliated pinne. Operculum funnel- or vase-shaped, thin when seen on edge, stall 
gradually dilating from the base upward, and with a brown margin, both stalk and operculum 
being pinkish orreddish. Body widest anteriorly, tapered posteriorly, and of a pale grass-green 
hue, or pinkish; it ends with a rounded papilla on each side of the anus; three pairs of 
bristle-bundles anteriorly, including the collar-fascicle, whilst the pale posterior region has 
nineteen to twenty segments. The colour of this species is reddish or greenish; a bright red 
hue tinges the opercular stalk as well as the base of the branchial filaments. The contained 
ova are likewise of a reddish colour. The collar-bristles are directed forward, have a long 
straight shaft which dilates as it approaches the backwardly curved tip, with serrations 
increasing in strength toward the notch, and then a few distinct serrations followed by a 
more finely serrated edge of the tapered blade. They are mingled with more slender, simple 
bristles having taperme tips. The two following pairs of bristles are simple, with spear-shaped 
slightly curved tips. Posterior bristles (two in each segment), with tips bent at an angle and 
resembling an ancient long-toed boot, with a serrated edge. Anterior hooks avicular, with a 
long serrated anterior edge, the main fang inferiorly being peculiarly modified and set at a 
slightly different angle. Posterior hooks smaller, but of similar structure. Tube sinistral, 
two deep grooves, and three ridges on the outer whorl ; often umbilicated. 
Few forms appear to have had greater vicissitudes in nomenclature than Spivorbis 
granulatus, L., a species which essentially difters from the Spirorbis granulatus, L., of Caullery 
and Mesnil' from Greenland and Nova Zembla, since the globular form of the operculum 
as figured by the French authors, no less than its ovigerous character, separate it from 
the present species, which, as Fleming® truly said in 1825, occurs “ on old shells, but more 
frequently on the under side of loose stones about low water-mark, very common,” and is 
especially abundant on the rocks and stones in rock-pools at St. Andrews. It is remarkable 
that two forms so closely resembling each other in many particulars should diverge so widely 
in regard to reproduction. Another name will be necessary for the northern form with the 
opercular brood-pouch, unless it 1s to be supposed that such a modification is possible in 
this example of a plastic group. In the earlier accounts of the species no mention of 
opercular incubation is made, and as the great majority of authors appear to have inter- 
preted this as the type, it remained for those who first described the opercular brood-pouch 
to characterise the form anew, and not to confuse the synonymy by adhering to the old title. 
It is certain that the majority of British and other northern zoologists interpreted the 
description of Linnzeus as applicable to the common littoral species which deposits its 
ovigerous string in the tube. 
SYNONYMS. 
1767. Serpula granulata, Linneeus. Syst. Nat., xii, p. 1266. 
1768. x # Pennant. Brit. Zool., iv, p. 359. 
1769. Tubularia viscera avium, Martini. Conch., pl. iii, fig. 23. 
1 “Bull. Se. France, Belgique,’ t. xxx, p. 216, pl. x, fig. 26. 
* «Hdin, Philos. Journ.,’ vol. xii, p. 244. 
