58 THE NAUTILUS. 



P. 8, line 22 Scacchi should read Brocchi. 



11, 22 plicala pHcatula. 



17, 22 1853 1833. 



18, 20 p. 59 p. 8. 

 30 1879 1899. 



29, 3 plicata plicatufa. 



1 4 plicata plicatula, 



15 plicatus plicatulus. 



It is interesting to note that these errors are indexed. 



On p. 18, line 27 as reference to (41) is given Proc. Royal Soc. 

 Tasmania, 1877, p. 152. The correct quotation is Trans. Roy. Soc., 

 South Australia, Vol. XXIV, p. 98, 1900. 



DESCRIPTION OF A NEW LYMNAEA. 



BY F. C. BAKER. 



EMARGINATA WISCONSINENSIS nov. var. 



Limnoea ampla Whiteaves (not Mighels), Can. Nat. and Geol., 

 VIII, pp. 102, 112, fig. 11, 1863. Taylor, Ottawa Nat., VI, p. 35, 

 1892. 



Shell very large, varying from elongate to globose, inflated, usu- 

 ally rather thin ; periostracum varying from light yellowish horn to 

 chestnut ; nuclear whorls as in emnrginata ; sculpture as in emargin- 

 ata ; many specimens have, in addition to the spiral impressed lines, 

 a number of heavy, more or less equidistant, spiral ridges encircling 

 the body whorl ; the last whorl may also be somewhat malleated ; 

 whorls 5 to 5^; globose, roundly shouldered, inflated, the body whorl 

 very globose and disproportionately swollen ; spire varying from 

 broadly acute to flatly depressed, usually about half the length of the 

 entire shell ; suture well marked, often deeply impressed ; aperture 

 roundly-ovate, rarely quadrate, seldom flaring ; peristome with in- 

 ternal, varical thickening ; inner lip wide, whitish, broadly reflected 

 over the umbilical region producing a wide, flat expansion, which 

 emarginates the umbilical chink, as in the typical form ; umbilical 

 chink usually very large and conspicuous ; imperforate individuals 

 are rare ; the parietal callus is thick and wide producing a continu- 

 ous aperture in some specimens ; the lower part of the aperture is 

 somewhat effuse in a few individuals. 



Length, 23.50; breadth, 15.00; aperture length, 13.00; breadth, 

 7.50 mill. 



Length, 22.00; breadth, 15.00; aperture length, 12.00; breadth, 

 8.00 mill. 



Length, 24.00; breadth, 16.00; aperture length, 13.50; breadth, 

 9.00 mill. 



