380 i'rof. h\ M'Coy on new Species of Fossil Volutes. 



bercle ; a narrow, step-like, undulated, flattened or slightly con- 

 cave space extends to the suture perpendicular to the axis; 

 lower or anterior half of body-whorl strongly marked with trans- 

 verse or obliquely spiral deep narrow sulci, having broader flat- 

 tened spaces between them, occasionally extending more faintly 

 a further variable distance towards the suture ; mouth with a 

 slight posterior channel, oblong, narrowed in front ; outer lip 

 smooth within (edge sometimes very faintly crenulated in old 

 individuals); inner lip slightly curved, with four slender, oblique, 

 nearly equal plaits about the middle, the anterior slightly longer 

 than the posterior; occasionally traces of a very small fifth plait 

 occur. 



Usual length 1 inch 9 lines ; body-whorl -^^ to -,s^, penul- 

 timate whorl -fLjS- to -rVo ; width -^^ to ^^. Young, 5 lines 

 long, body-whorl -y2J_, penultimate whorl -^^^ ; width -^-g : at 

 this size only three sculptured whorls at the pullus, twenty-two 

 ribs on body-whorl. Some species show that the mouth was 

 dark violet within. 



From the examination of a great number of specimens from 

 the Lower Miocene or " Tongrien " beds of Lattorq, near Bem- 

 berg, I long ago satisfied myself that the V. suturalis and V. 

 cingulata of Nyst were only extreme varieties of one species; and 

 Beyrich seems somewhat inclined to the same opinion, from ex- 

 amination of a larger number of specimens from other localities, 

 of one of the varieties at least, than Nyst seems to have had of 

 either, as he marks them both as rare in his ' Coquilles et Poly- 

 piers Fossiles de Belgique ;' and the latter name would be the 

 best to retain, as it indicates the remarkable girdling of the 

 whorls by the deep sulcus or constriction which seems to cut off 

 a subsutural row of tubercles from the ends of the longitudinal 

 ribs in the most common variety ; still, as in the V. bulbula, 

 Lam., to which Nyst likens the V. suturalis, specimens may be 

 found showing all the transitions between the most strongly 

 marked subsutural sulcus and its entire absence. The latter 

 variety I mark /S. indivisa; and in it the ribs are often fewer and 

 more sigmoid, and the shell narrower, than in the ordinary forms, 

 though none of these characters are constant ; in this variety, 

 too, the spiral strise are often confined to the anterior base of the 

 shell, leaving the body intact and the ribs smooth and polished. 

 Var. «. perstriata has the ribs rather more numerous and 

 straighter than in the ordinary type, and the spiral strise very 

 strongly marked over the whole body-whorl and spire, so as to 

 be in this respect intermediate between the Hampshire Barton 

 Clay V. ambigua and V. digitalina. In this variety the teeth 

 sometimes reach six or seven; the obtuse swollen papillary 

 "pullus^' to the top of the spire readily separates it on compa- 



