Victorian Fossils, Fart XIX. 95 



Occurrence. — Silurian (Yeriiigian). Cave Hill, Lilvdale. Young 

 forms in Rev. A. W. Cresswell collection. 



Cifclonema australis, Etheridge fil. 



(l.)Cyclonema australis, R. Etheridge, jnr., 1890. Rec. Aust. 

 Mus., vol. I., No. 3, p. 63, pi. IX., fig. 45. 



Gifclojiema australis. Idem, 1891, ibid., vol. I., No. 7, p. 127, 

 pi. XIX., figs. 1, 2. Chapman, 1913. Rep. Aust. Assoc. Adv. Sci., 

 vol. XIV., p. 227. 



Observations. — This species is separable from C. lilydalensis by 

 the stronger liration of the shell-surface, and the more distinct and 

 thread-like ornament crossing the interspaces between the spiral 

 ribs. 



Occurrence. — Sihirian (Yeringian). In limestone, Cave Hill, Lily- 

 dale. Rarer than the preceding species. 



Fam. Delphinulidae. 



Gentis C rasped OStom a, Lindstrom. 



Craspedostomn Wydalensis, Cresswell sp. (Plate IV., Fig. 37). 



Naticopsis lili/dalensis, Cresswell, 1893, Proc. R. Soc. Vict., vol. 

 V. (N.S.), p. 44 (name only), pi. IX., fig. 7. 



Cras2)edostoma lihjdalensis, Cressw. sp.. Chapman, 1913. Rep. 

 Aust. Adv. Sci., vol. XIV., p. 227. 



Description of Type. — Shell naticoid, with a short, rather 

 ■depressed spire of about three whorls and a large Ijody whorl. 

 Whorls inflated and ornamented Avith an obscure open cancellated 

 structure consisting of flattened spiral and longitudinal ribs. Base 

 umbilicated. In a supplementary specimen a part of the columellar 

 area of the everted lip is preserved, which shows relationship to the 

 above genus. 



Dimensions. — Compiled from both examples, and approximate 

 only. Width at base. 27 mm. Height of complete shell, circ, 

 ■22 mm. 



Observations. — The present species approaches very closely Lind- 

 strom's Wenlockian form, C. elegantidum,'^ in which, hoAvever. the 

 ribs are thinner and more conspicuous. In the comparative smooth- 

 ness of the whorls it shows some relationship also to C . filistriatum, 

 Lindstrom. 2 The genus appears to be restricted to beds of the 

 Upper Silurian epoch. 



1 Kongl. Svenska Vet.-Akad. Handl., Bd. xix., No. 6, 1884, p. 183, pi. ii., fig. 58 ; pi. xxi., fi;js. 

 ^20•29. 



2 Ibid., p. ISa, pi. xxi., figs. 35-38. 



