26 Frederick CJiapmarh : 



Observations. — Some of the shells of this freshwater or brackish 

 lacustrine species have as many as six whorls. The periostracum. 

 having been removed by natural decay, the ornament is clearly 

 seen as a longitudinal striation with occasional stronger varicial 

 striae, crossed by finer lineations. The young examples of about 

 three whorls are not decollated, the protoconch showing as a smooth 

 depressed spiral of about one and a-half whorls. 



The cleaned surfaces of the shells point to a slight age for 

 this deposit, although it should be borne in mind that the margins' 

 of some swamps where this S23ecies abounds are covered with layers 

 of the shells in this condition. 



C. sfriatvla is a very widely distributed form in Australia. 



Occurrence. — Common in the Boneo Swamp deposit. 



Fain PLANORBIDAE. 



Genus BULLINUS, Oken. 



BiiUimis aci/flspira, Iryon, sp. Plate III., Fig. 4. 



Physd ocut.ispira, Tryon, 1866, Amer. Journ. Concli. vol. 

 II. p. 9, pi. II., Fig. 10. Tate and Brazier, 1881,. 

 Proc. Linn. Soc. N.S. Wales, vol. VI., p. 557. Smitli, 

 1882, Journ. Linn. Soc. Lond. Zool., vol. XVI. p. 282, 

 pi. VI., Fig. 16. Clessin, 1885, Conch. Cab., vol. L 

 pt. 17, p. 242, pi. XXXIV., Fig. 1. 

 Btdlinus acutispira Tryon sp., Hedley, 1917, Rec. Austr. 

 Mus., vol. XII., No. 1, p. 5, pi. I., Figs. 11-13. 

 Observations. — The present speciments of these freshwater shells 

 from Boneo Swamp are of thicker build than the var. yarraeiisis, 

 T. Woods. 2 and are therefore referred to the type species. 



BuUinus tasmanicns, T. Woods sp.^ closely resembles the alx)ve 

 species, but the apex is not so acute, nor is the aperture so open. 

 Tbe species and variety have been recorded from Horsham, Cape 

 Grant, near Portland, Yan Yean Reservoir, Bunyip River, and 

 Carrum Creek, Frankston. One of tlie Boneo Swamp specimens 

 has an elongated spire, and resembles the figured specimen of 

 Hedley's, from Horsham. 



Occurrence. — This specimen is fairly numerous in the Boneo- 

 Swamp material. 



2. Phijsa yarraensis. T. Woods, Proc. Roy. Soc. Vict. Vol. XIV., 1S78, p. 64. 



BulUnns acutispira, Tryon, sp., var. yarraensis T. Woods var. Hedley, 

 1917, Rec. Austr. Mus., Vol. XII., No. 1, p. 5, pi. II., Fig:. 16. 



3. Physa tasmanica, T. Woods, Proc. R. Soc. Tasmania, for 1875 (176), 



p. 74. BulHnits tasmanicns, T. Woods, sp. Chapman, Mem. Nat. Mus.,. 

 Melbourne, No. 5, 1914, p. 58, pi. I., Figs. 5, 5a. 



