AMPHIDKOMUS. 127 



above, yellow and smooth below. Pattersonia. Fig. 85 is clear 

 greenish-yellow with a single dark belt; sculpture faint. Cataract 

 Hill. Fig. 92 is a very long shell from Port Davey, on the extreme 

 southwest of the island (Tenison-Woods). Figs. 89, 93 are extreme 

 forms from Ringarooma (Tenison-Woods). 



It is extremely probable that a number of distinguishable local 

 races exist, but they should be studied by some one familiar with the 

 local conditions, and with ample geographic series. 



Genus AMPHIL>ROMUS Albers, 1850. 



Amphidromus ALBERS, Die Hel. 1850, p. 138 (in part). MAR- 

 TENS in Die Hel. 1860, p. 184, type B. perversus Linn.; Ostas. Zool., 



Landschn., p. 332. SEMPER, Reisen, p. 146 FULTON, Ann. and 



Mag. of Nat. Hist. (6), xvii, pp. 66-94. 



Shell of moderate size, dextral or sinistial, long-ovate, with 6-8 

 moderately convex whorls ; smooth (rarely ribbed) and light or 

 bright-colored, yellow predominating, often with green or brown 

 streaks, flames or bands. Apical whorls smooth or obsoletely pitted. 

 Aperture somewhat oblique, ovate, not contracted by teeth or folds; 

 peristome more or less thickened, expanded or reflexed, the colu- 

 mellar margin reflexed, with a very weak fold or none. 



Jaw thin and weak, with flat ribs crenulating the edges. Radula 

 with broadly V-shaped rows, the teeth of "arboreal" type, with the 

 side cusps brought near the median cusp, all the cusps broad ; out- 

 wardly the side cusps are split. Kidney extremely long and narrow, 

 with reflexed ureter and closed secondary ureter. Genitalia of typi- 

 cally epiphallogonous structure; receptaculum seminis on a long, 

 simple duct; penis short, with the retractor muscle inserted low, and 

 ending in a flagellum and the vas deferens. Nervous and retractor 

 systems Helicine. 



Type Helix perversa L. Distribution, Sylhet Hills and Indo- 

 China to Timor, east to Mindanao and possibly the Moluccas. 



Without ample illustration the internal anatomy cannot be fully 

 discussed ; but from the data supplied by Semper, Wiegmann and 

 Jacobi, it is clear to me that the genus does not belong to the Buli- 

 inuUdce but to that group of Helicidce called Ephiphallogona,Qf which 

 the genera Ohloritts, Obba, Planispira and Papuina are leading mem- 

 bers. The exact inter-relationships of the genera of this group require 

 further elucidation. We know that Planitpira, Chloritis and Thersites 



