PLETHOTOMA. 387 



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lial tube long and cylindrical : head short, cloven in front : 

 tentacles cylindrical, mere club-shaped and slender points above 

 the eyes, three or four times as thick below them : eyes placed 

 outside the tentacles, at the extremities of very long stalks, 

 which are conjoined with the tentacles in the usual manner : 

 foot elongated, truncated or bilobed in front, with angular 

 corners, bluntly pointed or sometimes swallow- tailed behind : 

 odontophore simple ; pleura? diamond-shaped, with a minute 

 notch just below the middle on the inner side. 



Shell spindle-shaped, having the base broader than the 

 apex, rather solid, nearly opaque, of a dull but smooth aspect : 

 sculpture, broad and rounded, although not prominent, some- 

 what nexuous longitudinal ribs, which are more or less wanting 

 on the body-whorl and do not extend to the base or suture ; 

 there are 10 or 11 on each of the preceding three whorls ; the 

 space below the suture is girded by a thickened rim, and is 

 always ribless ; the whole surface (except the apex) is covered 

 with exceedingly numerous and fine spiral striae, which are 

 crossed and indistinctly beaded by still more delicate nexuous 

 striae in the line of growth ; the spiral striae on the body- 

 whorl alternate in size, but elsewhere are equal ; the third 

 whorl has four rows of spiral striae, which are not beaded 

 as in the foregoing two species; top whorls quite smooth 

 and lustrous : colour yellow, variegated with chocolate ; the 

 former colour is more perceptible as a broad band round 

 the upper part of the body-whorl, and on the ribs in the 

 other whorls, the interstices of the ribs in all the whorls 

 being of the darker colour ; apex chocolate : spire tapering to 

 a somewhat abrupt point : whorls 9-10, moderately convex and 

 rounded, shelving upwards, not angulated by the ribs ; the 

 last whorl occupies seven-twelfths of the shell : suture shallow: 

 mouth obliquely lozenge-shaped, compressed and acute-angled 

 above, broader at about one-third from the upper part ; length 

 five-twelfths of the shell: canal very short, wide, and trun- 

 cated, turning slightly but abruptly to the left ; basal notch 

 incurved, conspicuous on the outside : outer lip curved ; edge 

 blunt and even : labial notch broad and rather deep, placed 

 below the sutural rim : inner Up slight, but more spread and 

 not so retired as in many other species: pillar broad and 

 nexuous. L. 0-6. B. 0-225. 



Var. minor. Dwarfed or stunted, and more slender. L. 0*3. 

 B. 0-1. 



Habitat : Between tide-marks in Belgrave Bay, 



s2 



