100 Proceedings of the Royal Society of Victoria. 



some of the characters of the aperture. Specific name in honour 

 of Professor W. Baldwin Spencer, of the Melbourne University. 



36. Voluta atkinsoni, sp. nov. Plate III., fig. 1. 



Shell large, with a mammilate apex and a short conical spire, 

 succeeded by a very large, broad, and strongly shouldered body- 

 whorl, bearing coarse oblique nodosities at the shoulder, with an 

 aperture more than twice the length of the spire. 



Apical angle about sixty degrees. Mammilate apex of about 

 one-and-a-half smooth embryonic whorls, which are obliquely 

 enrolled, extreme tip eroded in the example before me, but pro- 

 bably somewhat exsert from its appearance. Succeeding whorls 

 five, suture defined, faintly undulatory, l)ut not impressed. Spire 

 very short, conical, with a slightly concave slojDe, rather suddenly 

 expanded into the large broad body-whorl, which is nearly four 

 times as loiig as the spire and a little more than twice as broad. 

 Spire-whorls bearing short, broad, costas-like nodules, which num- 

 ber about ten to a whorl, reaching from the anterior suture to 

 about the middle of the whorls, thus making the anterior slope 

 of these whorls a little convex, whereas the posterior slope is 

 concave. Body-whorl strongly shouldered, posterior slope con- 

 cave, anterior slope gently convexly sloping to the attenuated 

 anterior end ; on the shoulder there are ten strong oblique nodu- 

 lations, some of which tend to extend down the whorl and 

 develop into sigmoid costfe. 



Aperture prolate-ovate, somewhat effuse anteriorly. Inner lip 

 with a moderately thick enamel pad at the posterior end, poste- 

 rior canal shallow and narrow ; outer lip thick, bevelled off from 

 within, with a moderate outward reflection and a steep and rapid 

 ascent to the nodulations of the penultimate whorl ; anterior end 

 of margin where it joins the short and rather broad canal is a 

 little shorter than the columella side. Columella long, stout, 

 slightly twisted, bearing rather high up three unequally sized 

 oblique plaits, the anterior of which is the strongest ; the plaits 

 are not easily seen from a front view, as they are situated well 

 within the interior of the aperture. 



Surface ornament in addition to the nodular characters already 

 descrilied consists of fine close spiral threads, with shallow inter- 



