Dr. W. C. Mcintosh on the Boring of certain Annelids, 287 



low- water mark, my attention having been first directed to the 

 latter site by Dr. Bowerbank, who kindly sent me dried spe- 

 cimens. In these caves the tube of the Annelid is often coiled 

 in its groove beneath the Balani^ and then pierces the shell of 

 the latter to appear on the upper surface. It likewise bores 

 abundantly in Gellepora pumicosaj and in one instance had 

 bored quite through the valve of a living Pecten pusio. It 

 often occurs in the same oyster-shell in a combined attack 

 with Gastrochcena duhia^ Leucodore^ and boring sponges, or 

 sometimes places its tubes in groups in convenient fissures of 

 the shell without boring, so that they can be dislodged en 

 masse like short and contorted tubes of Tuhularia indivisa. 

 Another site is under empty limpet-shells amongst muddy 

 debris, part of each tube being inserted into a perforation in 

 the shell ; while, again, the cracks and fissures of the rocks 

 near low-water mark afford a very favourite habitat in the 

 Channel Islands, and their tubes are often seen projecting 

 through incrusting sponges and Ascidians, both simple and 

 compound. The species has a tough horny tube, whose ex- 

 posed portion is furnished with minute grains of sand ; but the 

 immersed portion is hyaline and more delicate. The boring 

 in the shell and limestone is circular, and, though often more 

 or less curved or coiled, it is not to be confounded with the 

 work of Dodecaceria or Leucodore. I need not allude further 

 at present to the structure of the species, save to observe that 

 its branchiae are speckled with pale green and white, and fur- 

 nished with two or three brown pigment-specks exteriorly, 

 and that its hooks (PL XX. figs. 5 & 6) (which are accompanied 

 by broadly spear-tipped minute bristles, fig. 7) and bristles 

 (fig. 8) have the structure represented. The body shows a 

 distinct acid reaction towards the posterior end, and especially 

 at the tip of the tail. 



The fourth native borer is a little SipunculuSj which exter- 

 nally appears to be identical with 8, Johnstoni of Forbes. It 

 occurs in limestone on the shores of the Isle of Wight, bores 

 into the spreading base of Corallina with the foregoing forms 

 in the Channel Islands, tunnels the mud in the fissures of 

 various rocks, and one occurred in a shell sent by Mr. Gwyn 

 Jeffreys in his rich Zetlandic collection of 1867. The form of 

 the perforation in the latter case is club-shaped ; and a young 

 specimen had bored its tiny gallery from the tube of its parent 

 — a very rare occurrence amongst the true Annelids. In this 

 instance the tubes of Campanularia verticillaia had taken 

 possession of several of these minute galleries after the death 

 or exit of the original inhabitant. This boring Sipunculus is 

 quite neutral to test-paper. 



20* 



