follov/ing dimensions: lat., 1?,.5 mm.; alt., 12 mm.; diara., 5.5 

 mm. ^ome soall riffht valves are decide^'^ly more convex and hip-her 



than the averf-^e form. Adult EhollE arc hesvier, r.lth the internal 

 flutings iiieonspic ous and the baual angle niore or less straight- 

 ened. In view of the la r~e size of some of the va?i.ves in the 

 Gollections '"hioh hsve furnished the inaterial for this at:-'!;;:, it 

 is evident that jamaieensis is larger than nii s s i s s i p;oi ens i s . The 



Bowden form is closer to V. c uad ranc-^-.l ar is Aldrieh (1), from the 



(1). Nautilus, vol. 16, no. 9, p. lOl, :ol. 4, figs. 22, 2?, 1903. 



siej 31ufi Oli'^ocene, but that species is heavier, ?vith a more 

 decided ventral angle on adult shells, fewer and voider ribs and 

 narrower intersoaces. 



Ocourrence .- Lower Miocene : Bowdon beds, Bowden, Jamaica 

 (Dall, 1905). 



