Mr. A. Hancock on Vermiform Fossils. 453 



groove may indicate the falling-in of the roof of a tunnel ; but 

 from its great similarity to the track of Kroyera arenaria, it is 

 more probable that, like it, it is a mere surface-ran formed by 

 the exposed animal ploughing its course. However this may 

 be, its nature cannot be questioned ; it is undoubtedly a track, 

 and so closely resembles those of the crustacean as scarcely to 

 leave room for the interrogation, Of what ? It is hardly to be 

 doubted that they belong to some animal of that class. 



From the above observations we seem justified in concluding 

 that these curious vermiform fossils are the tracks of crustaceans ; 

 but before doing so, it would be well to inquire how far they 

 are likely to be the remains or tracks of worms, or worm-tubes, 

 or any other organic body. 



In the first place, the enormous length of the grooved and 

 nodulous forms is rather opposed to their being the remains of 

 worms. Of course this does not militate against their being 

 worm-runs, though the great width they sometimes attain does 

 not at all favour that opinion. The width of the largest speci- 

 mens of the grooved form is a little over an inch, and of the 

 nodulous species about half an inch ; their length may be three, 

 ten, or twenty times greater than the measurements before given, 

 as none of the larger specimens, as already stated, have yet been 

 obtained with both extremities perfect. Size alone, however, is 

 not sufficient to debar the possibility of their having been formed 

 by worms ; but, upon such a hypothesis, how are we to account 

 for the peculiar character of the nodulous form ? It is impossible 

 to comprehend how the nodules, which are imbricated, passing 

 diagonally through the track, could have been produced by a worm 

 working its way through sand, mud, or any other material what- 

 ever. With respect to the grooved form, it may also be asked, 

 do worms or any of the Annelides ever make runs at all similar 

 to it ? I know of no instance of any of these animals making a 

 tunnel-track immediately beneath the surface of the beach, con- 

 fined to the same horizontal plane, and with an elevated, arched 

 roof. Annelides do not move along the surface in this manner ; 

 and when they burrow, they dip downwards, making perfectly 

 circular passages. 



The small furrowed kind, for size, might very well be the track 

 of some worm ; but its close resemblance to the runs of crusta- 

 ceans has already been pointed out. With regard to the small 

 cylindrical runs, not much can be said, as they are too deficient 

 in character to allow of any very decided opinion ; only we have 

 seen that on the beach there are elevated cylindrical tracks pro- 

 duced by crustaceans not very dissimilar to those in question. 



Can the two former or large species be worm-tubes, or any orga- 

 nic body ? The transverse striation on the surface of the grooved 



Ann. $ Mag. N. Hist. Ser.3. Vol. ii. 31 



