Victorian Fossils, Part XIX. 85 



Although rehxted to Ilormotoma by the form of the hxter whorls 

 •and the position of the slit-band, the open and persistent umbilicus 

 is a very distinct feature in the shells under notice. Consequently 

 forms of this type of Devonian age were generically separated as 

 Coelocaulus by Oehlert in I888.1 In 1897 Ulrich^ referred the 

 Onondaga (Silurian) species, Mtirchisonia logani, to the same 

 genus. 



Coelidium was more recently suggested as a genus name to 

 replace Coelocaulus by Clarke and Ruedemann,^ but has not been 

 adopted, even in America, apparently on insufficient grounds of 

 pre-occupation. 



The Australian Silurian and Devonian faunas both contain 

 rejDresentatives of this interesting genus. In 1877 de Koninck 

 described a Devonian species from the Yass district in New South 

 Wales under the name of 1 Niso darwinii,* a form which undoubtedly 

 species congeneric with de Koninck's, from the Silurian of Cave 

 belongs to this genus. In 1890 Mr. R. Etheridge, jnr.,-'^ described a 

 Hill, Lilydale, Victoria, to which he gave the name Niso (Vetotuba) 

 hrazieri, at the same time remarking on the close correspondence 

 between de Koninck's and his species. 



Whilst examining some senile forms of the Lilydale specimens of 

 this type, and in particular one found by Mr. J. S. Green, I noticed 

 the presence of a sinus-band in the later whorls which confirmed a 

 determination as Murchisonia made many years ago by McCoy on a 

 Museum specimen presented by Dr. G. B. Pritchard. 



Referring in this place to other occurrences of Coelocaulus, we 

 may note Lindstrom's Silurian example — "Murchisonia" com- 

 jjressa^ from the Silurian of Gotland, which has a similar wide and 

 •open umbilicus extending apparently to the apex. 



The Upper Silurian of Petropaulowsk in the Russian Oural 

 appears to contain examples of this genus, represented by " Ceri- 

 thium" helmerseni, de Verneuil,'' judging from the form of the 

 shell with its compressed whorls ; but the figure does not indicate an 

 umbilicated base, nor does the description throw light on this point. 



1 Bull. Soc. d'Etudes Scientiflques d'An<j:ei's, p. 20. 



2 Geol. Surv. Minnesota. Palaeontoloj^y, 1897, vol. iii., pt. 2, p. 1019. 



3 " Guelph Fauna in the State of New York." University State of N. York, 57th Ann. Rep., 

 vol. iii., Mem. 5, 1903, pp. 65 and C7. 



4 Mem. Soc. Roy. Sci. Liege, 2nd ser., vol. ii., 1876-7. See also Mem. Geol Surv. N. S. Wales, 

 Pal. No. 6, 1898, p. 101, pi. iv., fig. 11. 



5 Rec. Austr. Mus., vol. i., No. 3, 1890, p. 63, pi. viii., figs. 4, 5 ; pi. ix., fiys. 2, 3. See also 

 Mem. Geol. Surv. N. S. Wales, Pal. No. 6, 1898, p. 101 (footnote). 



6 Kongl. Svenska Vet.-Akad. Handl., Bd. xix.. No. 6, 1884, p. 129, pi. xii., fig. 18. 



7 Geol. de la Russie D'Europe. Murchison, Verneuil and Keyserling, 1845, vol. ii., p. 342, 

 pi. xxii., fig. 4. 



