loS PROCEEDINGS OJ THE JIALACOLOGICAL SOCIETY. 



THE ANATOMY OF THE SUBGENUS BEDDOMEA AND THE 

 RELATIONSHIPS OF THE GENUS AMPHIDROMUS. 



By Henry A. Pilsbry, Sc.D., etc. 



Read Uth December, 1900. 



PLATE XVI. 



The subgenus Beddomea was established by G. JSevill ' for the 

 reception of a few Bulinii from Ceylon and southern India, grouped 

 around B. Ceijlanicus, Pfr., as the type species. The relationships of 

 the group have been variously estimated. Nevill himself says : 

 " Very closely allied to AmpMdromus, altogether distinct from 

 Geotrochus ; it takes the place of the former in southern India and 

 Ceylon, where AmpMdromus does not occur at all." Mr. Hugh 

 Fulton, in his "List of the Species of AmpMdromus" remarks 

 that Beddomea and Pseudopartula appear "to be, from their concho- 

 logical characters, sufficiently distinct to stand apart."'" 



The receipt of specimens preserved in formaldehyde, from Mr. 0. 

 Collett, enables me to present data showing the affinities of Beddomea 

 to be with AmpMdromus. Three species have been investigated : 

 ' Bulimus ' Ceylanicus, Pfr., from Colombo ; B. intermedins, Eve., 

 from Watawala; and B. albizonatus, Rve., from Galle. 



1. Amphidromus (Beddomea) intermediums (live.). — The repro- 

 ductive system (PI. XVI, Fig. 2) opens in the usual position near 

 the right tentacle. The atrium is small and short. The penis is 

 slender below, enlarging distally, the terminal half very much and 

 irregularly enlarged. Its internal walls, plicate below, become 

 smooth near the apex of the lumen (Pig. 2a). The penis terminates 

 in an epiphallus (epi.) scarcely shorter than the penis; near its base 

 the retractor muscle is inserted. Penetrating the penis, the epiphallus 

 ends in a very large and fleshy papilla, filling the pmial cavity 

 (Fig. 2a) ; beyond the epiphallus there extends a long flagellum (fl.), 

 the major portion of which is coiled in a plane, there being about 

 three spiral turns. The vas-deferens is convoluted at the beginning 

 of its free portion. The vagina is long ; spermatheca oblong, near 

 the heart, on a long duct, which is slender above, swollen below. 

 Other female organs are as usual. 



The lung (Fig. 6) is rather elongate. The pulmonary vein is 

 destitute of large branches, the venation is densest on the intestinal 

 side and near the pneumostome as usual, but well developed upon 

 the cardiac side of the lung also. 



The kidney is very long and narrow, fully four times the length 

 of the pericardium, and two thirds that of the lung, while the width 



Hand List Moll. Indian Museum, i (1878), p. 127. 

 Aim. k Mag. Nat. Hist., ser. vi, vol. xvii (18%), p. (i(i. 



