Victorian Fossils, Part XIX. 91 



ing of two or three whorls rapidly widening on the last turn, 

 with free surfaces. Exterior smooth. Aperture suboval to sub- 

 rhomboidal, the angulation when present, situated on or above the 

 median line of the periphery. From the penultimate whorl inwards 

 the shell is divided by deeply concave partitions, the concavity 

 outwards. In some cases the septa are numerous, simulating a 

 cephalopod, but distinguished by the absence of siphuncular 

 openings. 



Dimensions. — Greatest diameter of type specimen about 65 mm., 

 when complete. Width of last whorl at 30 mm. from aperture, 16 

 mm. Length of aperture, 24 mm. Greatest thickness of shell, 

 13 mm. 



Observations. — This species was formerly identified by myself 

 with Euomphalus disjuncfus, J. Hall,l to which species it bears a 

 close resemblance, and it was listed under that name in my paper 

 " On the Palaeontology of the Silurian of Victoria. "2 Upon a 

 closer examination of a fair number of sj^ecimens it was seen that 

 the Australian examples were distinct from those of Hall's species 

 from the Upper Pentamerus limestone of New York State, in having 

 a more truly euomphaloid sectional outline to the aperture, which 

 in ours is more ungulate, and in the closer coiling of the outer- 

 whorls. 



In Lindstrom's Euomplialus triqiiefnis,^ which I would refer to 

 Liomphalus, the outer whorl widens very rapidly, and the aperture 

 becomes everted on the margin, whilst the last quarter turn of the 

 whorl is remarkably free. 



In E. gotlandicus, Lindstrom,'' the shell is closely coiled, and 

 whorls are inflated, with subcircular aperture. The spire in this 

 form is also depressed, otherwise it would naturally fall into the 

 genus Straparollus. 



Another member of tliis genus is Euomphalus (Straparollus) cly- 

 mtniodes, J. Hall,^ from the Devonian of the United States and 

 Canada (Schoharie Grit, New York, and Upper Helderberg limestone, 

 near Cayuga, Ontario). This is a smaller shell than usual, the largest 

 being about two inches in diameter. It has about four or five 

 whorls as in the Australian species, but, unlike it, has them more 

 evenly increasing in diameter, whilst the volutions are not free. 

 The mouth is subovate. 



1 Pal. New York, vol. ii., pt. i., 1859, p. 340, pi. Ixv., fig. 8; pi. Ixvii., %s. 4a, 6. 



•2 Rep. Austr. Assoc. Adv. Sci., Melbourne Mtj,'., 1913, vol. xiv., p. 227. 



3 Kongl. Svenska Vet.-Akad. Handl., Bd. xix., No. 6, 1884, p. 140, pi. xiii., figs. 32-35. 



4 Op. cit., p. 139, pi. xiii., figs. 19-31. 



5 Pal. New York, vol. v., pt. ii., 1873, p. 62, pi. xvi., fig. 15; pi. Ixx., flars. 1-5. 



