Dr. F. A. Bather — Tube-building Fossil Annelides 487 



Ophiurids arid Asteroids, but there is nothing that is not echinodermal. 

 One could wish for rather more definite evidence as to the precise 

 locality and horizon of all our specimens, but it is at any rate well 

 known that the tubes of fish -debris occur throughout the Upper 

 Cretaceous rocks of South-East England, and one fails to see why the 

 animals that made them should not occasionally have mixed their 

 materials, as do their modern analogues. Here, however, we must 

 observe that fish-scales do not appear to be in common use among 

 modern tube-builders. 



The particular materials used in each case appear to depend not 

 merely on propinquity, but also on the ease with which the particular 

 species can use them. The relative weight of the materials, the nature 

 of their surface, or the differences of size may each or all affect their 

 adaptability to the creature's mechanical powers. Whatever be the 

 reason, certain species do, as we have seen, exercise a power of 

 selection, and to that extent the converse holds good, namely, that 

 tubes composed of obviously selected materials characterize diverse 

 species. 



All these considerations incline me to the conclusion that the remains 

 of fishes, plants, and echinoderms were selected by three different 

 species of worm. But before distinguishing these species by name, 

 I await such confirmatory evidence as would be afforded by the 

 occurrence of these three kinds of tube at the same level in a single 

 limited area. Some of our enthusiastic students of the Chalk will 

 doubtless be able to furnish the national collection with the desired 

 material. 



(To be concluded in our next Number.) 



EXPLANATION OF PLATE XXIV. 



Fig. 1. Keckia (?) sp. Probably Lower Cenomanian, South-East England. 

 B.M. 4784. 



,, 2. Granularia (?) sp. Albian, Gault, Folkestone. Portion of a small 

 slab covered with similar tubes. B.M. 39453. x 2 diam. 



,, 3. 'Terebella' cancellata, n.sp. Cenomanian, probably Holaster sub- 

 globosus zone, Glynde, Sussex. Holotype. B.M. 58253. 



,, 4. ' Terebella' 1 cancellata, n.sp. Probably same horizon, Cowslip Pit, 

 near Guildford, Surrey. Portion of the infilling of a tube. The 

 photograph shows the impressions, but does not bring out their 

 curved arrangement ; this has therefore been emphasized by a little 

 white paint along one curve. The diagonal striation is very clear 

 in the photograph, but is too fine to be reproduced by the half-tone 

 process ; one line has been emphasized, to show the direction. 

 B.M. A 1577. 



,, 5. 'Terebella' cancellata, n.sp. Same horizon and locality. Portion 

 of the infilling of a tube in which the longitudinal folds are strongly 

 marked. B.M. A 1574. 



,, 6. ' Terebella' lutensis, n.sp. Albian, Gault, Eastbourne. B.M. A 23. 

 x I. 



,, 7. ' Terebella' leivesiensis (?). Cenomanian, Dorking Pit, Surrey. Tube 

 made of conifer leaflets and bits of bark, imbricating. B.M. A1566. 



,, 8. ' Terebella' leivesiensis (?) . Cenomanian (?), South-East England. 

 Part of a wide tube of long conifer leaflets, irregular, but mostly 

 longitudinal. B.M. A 1568. 

 All figures are natural size, except Nos. 2 and 6. All are from photographs 

 by Mr. H. G. Herring. 



