III i 



ee. I.ateml MT6M uith L' :!. pleuni 1 1 rihl-K 



aa. < entral :uv:is .-moot!). lacking longitudinal ril 



b. Fnd valves un-aiio.-r-lirale or pu-tuloae. 



C. Fnmt ot'di:i;r<m:il line obviously wrinkled or jitti-l. 

 d. Shell and girdle uniform dark LI ru/ 



itl. Shell variegated, gird! -mated, afotrt. 



'/(A/. Shell or irinllr vnii'-l. BOalei smooth, viY/' 



l-'roiit of (liiiLronal line smootli. 



il. I'ustulcs .-<';itifi-nl : >iiril and girdle UDiform blackUb, 



mar 

 '/(/. Finely Ix-adcd ; ihell and girdle banded, .^/////?no. 



66. End valves finely striated. 



C. Shell oblon.ir. divergence about 110. 



Shell elongated : divt-rp-m''' about 98. f><< 



AA. LATERAL AREAS SMOOTH OR CONCI:VI 1:1- M .1 .v w n.i'irRED. 



a. Whole surface smooth. 

 b. Mucro near the anterior margin. 



c. Color black and olive-yellow, with snowy lines, (ilhu/in- 

 cc. Purple or olive mottled. 



d. Sutural-plates within dark-blotched at base; sinus nar- 

 row, ''j'ttiift. 



d<L Suttiral-plates within not blotched; sinus wide, 



marmoroto*. 



bb. Mucro central, tidipa. 



aa. Central areas longitudinally sculptured, (species not tabulated.) 



West Indian species. 



Mainly large forms, with smooth scales and notably anterior 

 mucro. They are closely allied to the species of the Panamic 

 region. 



C. TUBERCULATU8 Linne. PI. :53, figs. 58, 59, 60. 



Shell oval-oblong, rather elevated, carinated, thoide-slope- nearly 

 straight. Color varying from light olive to dark Driven <>r dark 

 olive-brown, unicolored sometimes, but generally speckled on the 

 side-areas and end-valves, often clouded on tin- central an 

 of the valves having a dark stripe on the ridge. 



Lateral areas raised, sculptured with about -\eord-like radiatm- 

 riblets, which are sometimes subcontinuous, but usually are much 



