Mr. Alder's Supplement. 337 



No. XVII. — Supplement to a Catalogue of the Land and Fresh-water 

 Testaceous Mollusc a, found in the Vicinity of Newcastle. By Joshua 

 Alder. 



Since the publication of the the Catalogue of Land and Fresh-water Mol- 

 lusca, in the first volume of the Society's Transactions, further investigation 

 has brought to light a few additional species and localities, which it is the 

 purpose of this communication to record ; together with some additional 

 remarks, and such corrections of the former list as increased information 

 renders necessary. Among the species included in this Supplement will 

 be found four or five now first described as British. 



Gen. LIMNEUS* 

 L. auricularius, Drap. 



In ponds at Prestwick Car. — Mr. A. Hancock. 

 L. ovatus, Drap. (Nat. Hist. Trans, vol. i. p. 30.) 



This may be reduced to the rank of a variety of L. pereger. 

 L. lineatus, Bean, in Loudon s Mag. vol. yii. p. 493, which I take to be also a variety of 

 L. pereger, occurs in a pond at Redheugh. The reversed variety has not been found here. 



PHYSA. 

 P. fontinalis. (vol. i. p. 30.) 



Additional localities — Mill stream, near Busy Cottage, Ouse Burn ; Mr. Brandling's 

 Lake, Gosforth ; Pond, near Marsden ; and Haughs below Ryton. 



PLANORBIS. 

 P. contortus. (vol. i. p. 30.) 



Additional localities. — Gosforth Lake ; Ryton Haughs. 

 P. Icevls. 



Shell flat, perforated on both sides, brownish horn-coloured, semi-transparent, smooth, or 

 slightly wrinkled by the lines of growth, with 3 to 4 compact and rounded whorls and a 

 nearly circular aperture. Diameter about l-8th of an inch. 



* This Genus is in the Catalogue written Lymncea after the orthography of Lamarck, but most modern 

 writers now agree in spelling it as above. 



