Dr. W. C. Mcintosh on the Boring of certain Annelids, 281 



it is not the helpless animal described by Dr. Johnston *, but 

 progresses very actively indeed, either on a horizontal or per- 

 pendicular surface ; and if circumstances are unfavourable for 

 its gaining the stone, or, if it so chooses, it fashions a tube 

 round its body with ease and rapidity (provided materials are 

 forthcoming), either on the bottom or along the side of the 

 vessel. Nor is it satisfied with the construction of one home, 

 but roams about from place to place and forms several. In 

 such instances the tube is not generally turned on itself, 

 but is more or less linear, the cup of the anal segment com- 

 municating freely with the water by the open end of the tube. 

 They are also not unfrequently found swimming on the sur- 

 face of the water, like other Annelids. 



The first point that strikes the observer in regard to the 

 perforations in the sandstone and shale is that they are grouped 

 in pairs, sometimes with a thicker and sometimes with a 

 thinner intervening column. In many cases this column would 

 seem to be formed of debris ; but in others, especially those in 

 shell, sandstone, and Gorallina^ some of the original material is 

 left ; so that, by this feature, the observer is seldom left in 

 doubt as to the identity of any particular gallery he encounters. 

 From the exterior the tubes, as usually observed, proceed in- 

 wards either as nearly straight or more or less curved cylin- 

 drical galleries, and terminate in the case of each pair by 

 joining in a loop at the bottom, the latter being either abruptly 

 or gently curved, according to the thickness of the intervening 

 column. This siphonal form of gallery is very general among 

 the Annelida and other burrowing animals ; various TerehellcBj 

 Eunice sanguinea^ Cirratulus cirratus^ and others follow this 

 habit in the fissures of rocks ; while Cm'ophium longicorne, so 

 abundant in company with Edwardsia on some of our muddy 

 or clayey shores, has its burrow of the same characteristic 

 formation. In Leucodore^ as a rule, the intervening column 

 attains the largest dimensions inferiorly, a considerable wedge of 

 sound shale being often left at the loop. The latter, moreover, 

 in some was marked by two or three grooves, showing that at 

 various times the animal had altered the depth of its galleries 

 to suit its convenience, perhaps in relation to the length of its 

 built-up or external tube, though this is not a matter of much 

 consequence. All the tubes were lined by the delicate secre- 

 tion before mentioned. 



In the borings in shell, NuUipore, and Gorallina the tube or 

 perforation had not, in our specimens, the form of a keyhole, 

 as mentioned by Mr. Lankester, but possessed a solid column 

 of the original structure, or else one of consolidated debris, in- 

 tervening between the tunnels. In the sea- worn specimens of 

 * Catalogue of Worms, Brit, Mus. p. 206. 



