536 Di\ F. A. Bather— The Mount Torlesse Annelid. 



The annelids secreting firm calcareous tubes do not, however, 

 appear to furnish any other genus with which comparison would 

 be profitable, and in general appearance this fossil most nearly 

 resembles certain fossils rightly or wrongly assigned to Serpula. 

 It is not the Mesozoic or Cainozoic species that it in any way 

 resembles, but certain Palaeozoic species, and of all these the 

 resemblance appears closest to the Carboniferous fossil named 

 Dentalium indistinctum by Fleming (1825) and Serpula compressa 

 by J. de C. Sowerby (1829). That species, however, which 

 certainly agrees with Serpula in its irregular curvature, and 

 probably in its partial attachment, further differs from the Mount 

 Torlesse fossil in the more rapid tapering and its relative tenuity 

 of its tube-wall, notwithstanding the fact that the wall is described 

 as " thick." It is thick relatively to the Palaeozoic serpuloids, which 

 therefore need not further be brought into comparison. 



It is probable, and has thus far been assumed, that the tube of this 

 fossil, though now chalcedony, was originally a firm calcareous 

 secretion, a view confirmed by the composition of the other Mount 

 Torlesse fossil. There is, however, just the possibility that the 

 tube was an aggregate of sand-grains as in Terebella. The tubes 

 of the various species of that genus differ from the present fossil 

 in their irregular growth, while the calcareous sand-grains of 

 which they are composed are certainly coarser than any which 

 could possibly have entered into the composition of the New 

 Zealand fossil. A much closer resemblance is presented by tubes 

 from the Yakutat Slates of Alaska, recently described by Mr. E. 0. 

 Ulrich (1904, p. 132) as Terehellina Palachei, gen. et sp. nov. ; 

 indeed, some of his figures (pi. xi, figs. 2, 5) might almost serve 

 as illustrations of our specimens. Terehellina is thus diagnosed : — 

 " Long, subcylindrical, gently curved and rather thick-walled tubes, 

 acuminate below ; surface obscurely striated transversely. Tubes 

 composed of cemented minute siliceous grains." These grains are 

 " essentially the same as those of the arenaceous shale in which " 

 the fossils " are found," but are " of more uniform and larger 

 average size in the tubes than in the matrix." The length, the 

 very gradual tapering, and the thickness of the wall ("about 

 two-thirds of the diameter is taken up by thf> central hollow ") 

 are all points of resemblance to our fossil. It is further note- 

 worthy that in Alaska as in New Zealand these peculiar worm-tubes 

 serve to correlate exposures of slate of undetermined age in widely 

 separated localities, and that the only other fossils are supposed 

 fucoids and, in one locality, a peculiar concentrically ribbed 

 Inoceramus-like shell. The Alaskan shell is named Inoceramya 

 by Mr. Ulrich, to express his opinion that it is intermediate 

 between Posidonomya and Inoceramiis. On the evidence of all 

 these fossils Mr. Ulrich assigns the Yakutat Slates to a Liassic 

 age. But, although it would be important as well as curiously 

 interesting to identify the Mt. Torlesse annelid with Terehellina, 

 this course does not appear possible. Apart from the absence of 

 any structure suggesting a similar constitution of the tube-wall, 



