156 M. M. SCHEPMAN, LAND- AND FRESHWATER MOLLUSCA, ETC. 



A. Land- and Freshwater-Mollusca. 



Class GASTROPODA. 



PULMONATA. 



Suborder Geo phi la. 

 A. MONOTREMATA. 



Fam. ZONITIDAE. 

 Xesta Albers. 

 1. Xesta citrina Linné. 



Linné. Syst. Nat. Ed. X, p. 771. 



var. cohimellaris Beck. 



v. Martens. Ostas. Landschn. p. 194, PI. 7, fig. 2, 6, 8. 



Reeve. Conch. le, Hélix, fig. 482^, 485^. 



Tapparone Canefri, Fauna Mal. New Guinea, p. 196. 



Tryon. Man. of Conch. Ser. II, Vol. II, p. 73, PI. 20, fig. 91, 95. 



New Guinea. Alkmaar, Sept. 18, 1907; 20, 1909; Nov. 1909; Bivak Island, Jan. 16, 20,1910; 

 Febr. 19, 1910; Mardi, 1910, July S, 10, 14, 15, 17, 18, 22, 1907; Aug. 15, 23, 24, 1907; 

 Sept. 15, 17, 24, 28, 1907; Oct. 1909; Geitenkamp, July, 20, 1907; Lorentz River, May, 9. 

 10, 11, 15 — 19, 1907; Sept. 5 — 12, 16, 1909; Pandanus Creek, May, 15,1907; Sabang, June, 

 10 — 24, 28, 1907; July, 4, 1907; Oct. 5, 1912 (Versteeg leg.). 



The spécimens belong to a small form, they corne very near to, but are not quite 

 identical with var. cohimellaris Beck from Ceram, the shells being smaller, scarcely exceeding 

 30 Mill. in their largest diameter, though collected at very différent times of the year, 

 whereas V. MARTENS describes them as from 33 to 38 mill., they are slightly smoother, the 

 purple umbilical patch, though présent in several spécimens, is wanting in the majority; the 

 reddish top, though mainly présent is much smaller. However I cannot see anything but a 

 small form of this variety in the numerous spécimens ; they agrée in the narrower last whorl 

 and in the thicker shell. The colour is in most instances yellow, with a dark peripheral band 

 and reddish apex, but some spécimens are yellow or white, without that band. They may in 

 part agrée with var. D. of Tapparone Canefri, but as he gives no measurements, this 

 cannot be made out with certainty. A few spécimens from Alkmaar, remind the description 

 of var. aplcata v. Moellendorff (Proc. Mal. Soc. Lond. Vol. I, p. 234) but that variety ought 

 to hâve the brown band only on the apical .whorls and in the spécimens under considération, 

 it extends still on the last whorl and leaves only part of that whorl free. 



var. fragilis n. var. PI. IV, fig. 1. 



Shell rather small, thin, fragile, smooth and shining, with moderate growth-striae, 

 violet-brown with a white apex, a white zone below the suture and it is sometimes also 

 whitish near the aperture, a darker peripheral zone is présent in some spécimens. 



Diam. maj. 31, ait. 21, apert. ait. 15, lat. 16 mill. 

 Lorentz River. Sept. 3 — 12, 1909. 



