232 F. Stoliczka — Notes on Terrestrial Mollusca. [No. 3, 



from the soft parts of the animal to the characteristic of the 

 genus. 



Foot about equal in length to twice the largest diameter of the shell, 

 moderately narrow, tail gland distinct with a small, obtuse, hook-like 

 appendage above it ; sole with two longitudinal furrows ; left shell-lobe 

 ivith a narrow appendage, originating some distance from the pulmonary 

 orifice, a little below the angular periphery of the last whorl of the shell, 

 and reflected over the basal portion of the last whorl only ; rigid shell- 

 lobe linguate, above fat the posterior angle of the aperture of the shell) 

 thickened, and beloio fat the columellar lip J slightly produced ; left dor- 

 sal lobe divided into two lobes, the upper linguate, the lower narrow, 

 sometimes nearly obsolete; right dorsal lobe large, considerably extend- 

 ing over the neck of the animal. Jaw semilunar, of nearly equal breadth 

 throughout, smooth ; rqglula ivith many median rows of subequal teeth 

 conspicuously larger than the outer teeth. 



It will be seen from this characteristic that I omit to make 

 reference to the form of the genital organs for reasons which I 

 hare already explained, but further on I shall give some anatomical 

 details of a species which, I believe, may be considered as one of the 

 typical forms of the genus, R. anceps. 



Semper (Eeisen im Arch, der Philipp., vol. Ill, pt. i, p. 38) 

 characterizes Rotula merely from a few anatomical characters which 

 appear to me very insufficient for such a purpose. He considers 

 Albers type as only doubtfully belonging to the genus, thus estab- 

 lishing the latter altogether upon a new basis, and placing IT. 

 ccelatura, Per., rufa, Lesson, Massoni, Behn, and Campbell i, Gray, 

 in it. Of these I would exclude the first named species ; the 

 form of its shell is quite different from those of the other species, 

 and the character of ornamentation indicates that the mantle lobes, 

 if any be present, must also be different; it besides has no appendage 

 above the tail-gland. The three other species I take, however, to 

 belong to Rotula. 



H. semicerina, Mori., ( = Raivsonis, Eeeve) is also referable to 

 Rotula; it is connected through implicata* Nevill, with H. arg en- 

 tea, E,eeve, and thus passes into the Trochomorpha type of shell, 

 though the animal is decidedly one of the Zonitidje. IT. cernica, 

 * Journ. Asiat. Soc, 1870, vol. XXXIX, pi. ii, p. 407. 



