3 1 PROCEEDINGS OF TTTF. MALACOLOOTCAL SOCIETY. 



sixty long, curved, aculeate laterals ; next follows a numerous bicuspid 

 series, in the outermost of which the cusps are even in length, the 

 uncini are very minute. There are 148 rows of teeth, arranged thus: 



204 : 2 : 14 : 1 : 14 : 2 : 204 



220 : 1 : 220 



The shell is very globosely subturbinate, with the side of the spire 

 convex ; a pale band borders the periphery above ; the umbilicus is 



4 mm. wide, and the columellar margin is obliquely curved to the 

 lower margin of the aperture. Size of the largest specimen 63-25 mm. 

 This fonn agrees well with H neptuna, Pfr., obtained by Monsieur 

 Mouhot in Siam, described in P.Z.S., 1861, p. 190, and figured in 

 the Novit. Conch., pi. xlviii, figs. 1 and 2, the open umbilicus being 

 well shown. 



Helix distincta, Pfr., is described in the Zeitschr. f. Malak, 1850, 

 p. 69, its habitat being the Moluccas. The shell is figured in 

 Chemn., 2nd ed., Helix, No. 863, pi. cxxxiv, figs. 1 and 2 ; from this 

 it is seen that the outline is not that of the Siam species, while the 

 umbilicus is very considerably smaller. The figure in the Conch. 

 Icon. (pi. lxxxvi, fig. 465) does not settle the size of the umbilicus, 

 only a frontal view of the shell being given ; the columellar margin 

 is represented as rather straight, and the habitat is said to be 

 unknown. 



Professor von Martens, in his list of Siamese land mollusca in "Die 

 Preuss. Exped. Ost-Asien," p. 69, records Nomina distincta as one { 

 of the largest and most abundant shells in Siam, and figures the 

 animal, pi. vi, fig. 8. He says : (1) the shell is narrowly umbilicated ; 

 (2) depressedly turbinate; (3) its size is 54mm. in major diameter; 

 (4) the jaw is plain and without a central projection. In all these 

 points there is disagreement with the species sent home by Mr. Daly. 



On looking up H. distincta in the Natural History Museum, on one 

 tablet are two shells under this name ; one is marked with a cross in 

 pencil, and on the back is written, " H. pluto, Pfr., Lao Mountains, 

 Cambodja, figured in Novitates, pi. lv, figs. 8, 9." The other is 

 marked with two crosses, and the coiTesponding note reads: — " var. 

 neptuna, young." Mr. Daly's shell agrees best with this specimen. 



Professor Semper, in his " Reisen im Archipel der Philippinen," 

 Bd. iii, p. 63, pi. vi, fig. 27, under Xesta distincta, mentions having 

 obtained two shells from Zamboanga, in Mindanao. He, however, 

 described the animal, and figured the jaw and radula of a young 

 specimen from Saigon, Cochin China, which is over 500 miles from 

 Siam. The jaw has no central projection ; the central tooth and 

 admedians are tricuspid, the laterals bicuspid, with 160 to 180 teeth 

 on each side of the radula. This description does not answer for 

 the jaw, the form of the teeth, or the dental formula of the Siam 

 species, which I identify as Hemiplecta neptuna. 



The question arises, does the anatomy of the species which Semper 

 identified as Xesta distincta from Saigon correspond with that of the 

 species in the typical locality Mindanao, and again, will this anatomical 



