208 LAND AND FRESHWATER 



Leptodontarion HiRASEANtJS, Pilsbrv. (Plate CXV, figs. 1-1 h ; 

 Plate CXVI. figs. 4-4 d.) 



Helicarion hiraseanus, Pilsb. Proc. Nat. Sci. Philad. 1905, p. 740. 



Animal (figs. 1 & 1 rt) with a long foot, keeled, a narrow band of 

 black rnnning down it ; mucous gland linear ; neck to e5-e-tentacles 

 black, the rest of body pale-coloured. Foot divided on sole ; peri- 

 podial grooves as usual. Right shell-lobe broad, reaching to apex 

 of shell, smooth ; left shell-lobe moderately broad, tongue-like, 

 narrowing to a point, also smooth and pale-coloured. The right 

 dorsal lobe slightly papillate, the left long and narrow, divided by a 

 slit into two. Visceral sac slightly spotted with black, and the 

 kidney has a narrow black margin on the right side. 



Genitalia (fig. 4). The penis (fig. 4 6) is a simple tube, with a 

 rather long retractor muscle at the usual bend, the epiphallus 

 moderately long and slightly swollen. The most interesting organ 

 is the spcrmatheca (figs. 4 & 4 a), which is stalk-like below, termi- 

 nating in a spherical sac. The oviduct was of great size in tlie 

 specimen examined, being a gelatinous mass ; the albumen-gland 

 (Al.gd.) also unusually large, compared with the penis and other 

 organs. 



The jaw (fig. 4 d) is thin and delicate in structure, with a slightly 

 curved cutting-edge. 



The radula (fig. 4 o) is a most delicate broad band, consisting of 

 certainly nearly 450, perhaps more, teeth in the row — a series all 

 alike, narrow, curved, and nearly evenly bicuspid, the central uni- 

 cuspid. The series of teeth narrow gradually from centre to margin ; 

 three or four of the outermost teeth on very edge of the radula 

 are serrated. It is preciselj' like that of Leptodontarion. figured by 

 the brothers Barasin in their work on Celebes, pi. xxviii. fig. 280. 

 The whole of the radula was got out, but it is unfortunately so 

 folded that I cannot count the teeth, and it was too brittle to 

 attempt any arrangement of the torn parts. The centre teeth are 

 well seen at one part. 



Original description : — " Shell imperforate, depressed-globose, 

 thin and fragile, pale amber-coloured, transparent. Surface very 

 glossy, smooth and polished. Spire convex, narrow. Whorls 3^, 

 rapidly increasing, the last rounded peripherally and beneath. 

 Aperture oblique, broadly lunate, the peristome with a narrow 

 refiexed cuticular edge. Columella simple, thin, concave. 



" Alt. 6, diam. 9-5 mm. 



" Sammaipo, Taiwan. Types No. 90, 235, A. N. S. Phil., from 

 No. 1431 of Mr. Hirase's collection. 



" Six specimens of this charming species were taken. No snail 

 of similar Vitrina-l\ko shape is known from Formosa, the llyukyu 

 Islands, or Japan." 



