Dr. F. A. Bather — Tube-building Fossil Annelides. 483 



however, I obtained a specimen from the Terebratulina zone near 

 Winchester, duly exhibited before the College Natural History 

 Society as ' a fossil fish '. Mr. T. H. Withers tells me that in 

 Oxfordshire and Surrey the species is common in that zone, as also 

 in the Rhynclionella Cuvieri zone of Surrey. 



Although this fossil is not noticed by name in his papers on the 

 Chalk, Dr. A. W. Howe kindly permits me to give as his experience 

 that it occurs in every zone of the White Chalk. It is, he says, rare 

 in the zones of Belemnitella mucronata and Rhynclionella Cuvieri, but 

 especially common in those of Marsupites and Micraster cor-anguinum ; 

 it is also common at Dover in the zones of If. cor-testudinarium and 

 Jfolaster planus. 



That these bodies were tubular was maintained by Davies, on the 

 evidence of specimens, not more precisely designated, in the British 

 Museum. Apparently the tubes have sometimes been flattened, at 

 least in part [23 158 J. Frequently they have an elliptical section, 

 probably due to post-mortem compression ; thus we find diameters of 

 18 and 12 mm. [A 1627], of 20 and 14 mm. [25876], of 22 and 15 mm. 

 [58262]. But that the tubes had a moderate amount of rigidity may 

 be inferred partly from the fact that the specimen last mentioned has 

 a core of flint, partly from specimen A 1629, in which a Spondylus 

 valve lyiug alongside has been broken by pressure against the tube. 



Considerable variations in the apparent diameter of the tube 

 (e.g. 30 and 20 mm. [A 1632], 20 and 13 mm. [25943]) are probably 

 due to crushing ; and this cause may also account for the appearance 

 of a short branch about the middle of the length (16 cm.) preserved 

 in A 1573, where the width at one end is 21 mm. but close to the 

 branch only 12 mm. There is a similar appearance in A 1567, made 

 of conifer leaflets. 



The maximum length of these tubes was given by Mantell as 2 feet, 

 but Davies maintained that they might have been longer "as no 

 specimen with the extremities entire has yet been discovered ". 

 I don't quite see how one is to decide whether an extremity is 

 entire or not, except by knowing that a piece was left behind in the 

 quarry, and certainly this has not been the case with all specimens. 

 The longest specimen in the British Museum is that figured in Dixon's 

 Geology of Sussex, pi. 34, fig. 5 [58261] ; it is 35 cm. long (a little 

 less than the " fourteen inches" assigned to it by Davies), and 35 mm. 

 wide; the included fin-rays, according to Davies, "exceed two inches 

 in length," and some are actually 10 cm. long, nearly 4 inches. The 

 horizon and locality of this specimen are unknown. The longest 

 specimen from the Mantell Collection [4126] is 29-5 cm. long and 

 20 mm. Avide ; it is said to be from the " Chalk, Lewes ". These 

 measurements do not follow the curves of the specimens. Davies 

 speaks of the " comparative straightness " of the tubes, but the longer 

 specimens, at least, are always curved and often markedly sinuous ; 

 thus, A 1629 is like an elongate^ with an approximate length of 

 20 cm. and a diameter of 16 mm., and shows no obvious signs of being 

 incomplete. 



The width of the tubes can rarely be measured with great exactness ; 

 as already mentioned it often varies, and is probably always exaggerated 



