594 GASTROPODA. [Pnlmonata 



guishable on account of the abrasions to which this shell is very sub- 

 ject. The apex of the shell may appear either on the left or on the 

 right, or almost central. The teeth on the inner lip may both be very 

 prominent, or the anterior one may be almost suppressed. (Iredale.) 



Genus 4. CREMNOBATES, Swainson, 1855. 



Crcmnobatcs, Swainson, P.R.S. Van Diemen's Land, iii, pt. 1, Jan. 1855, 

 43 ; not of Giinther, 1861 (Pisces), nor of Blanford, 1868 (Mollusca). 



Swainson gives the following diagnosis : ' Animal amphibious. 

 Shell small, oval. Spire rather pointed, as long as the -aperture. 

 Aperture not contracted. Pillar with strong plaits. Inner lip thin, 

 smooth inside." Three species are enumerated --( 1 ) C. cornea, 

 (2) C. parva, (3) C. solida but the, first is Ophicardelus australis, 

 Q. & G., and the third Marinula patula, Lowe, leaving C. parva as 

 the type of the genus. 



Animal (in alcohol) with short tentacles, the eyes at their inner 

 bases ; foot long and narrow, truncated in front, narrowly rounded 

 and simple behind, with a distinct transverse groove at the anterior 

 third of length. Jaw horny, arcuate, with a median projection below 

 and a shallow sinus above, vertically narrowly striated, the cutting- 

 edge serrate. Radula broad and long, with numerous transverse 

 slightly arcuate rows of minute teeth, which are exceedingly numerous, 

 with a long and narrow base, and a minute cusp. I was unable to 

 distinguish a central tooth distinct from the other teeth. 



Shell small, oval, smooth, the spire as high as the aperture or a 

 little less ; aperture ovate, not contracted ; the outer lip thin and 

 simple ; columella with 2 strong plaits on the upper half. 



Distribution. Tasmania. Antipodes Islands. Islands of St. Paul 

 and Amsterdam. Tristan da Cunha. 



Mr. Charles Hedley kindly informed me that the following species 

 are no doubt members of the genus : (1) Marinula Maindroni, Velain, 

 Archiv. Zool. Exper., vi. 1877, 126, pi. 4, f. 26, from Amsterdam 

 Island ; (2) Marinula nigra, Philippi : Velain, op. cit.. 125. pi. 4, f. 25, 

 from Tristan da Cunha, St. Paul, and Amsterdam Islands. Thus 

 the genu* would appear to be of nearly circumpolar range. 



1. Cremnobates parva, Swainson, 1855. Plate 24, fig. 5. 



Cremnobates parva, Swainson, P.R.S. Van Diemen's Land, iii, pt. l,;,Jan. 

 1855, 44, pi. 7, f. 3. Ophicardelus parvus, Swainson (Cremnobates) : Tate 

 and May, P.L.S. N.S.W., xxvi, 420. 



Shell ovate, thin, light, covered with an epidermis ; spire slender, 

 pointed ; pillar plaited : the first plait close to the top of the aperture, 

 the second more towards the base (Swainson). Sculpture consisting of 

 well-marked growth-lines. Colour whitish or light brown, the mouth 

 light to dark brown. Epidermis thin, horny, lost in most of my 



