233 
Nr. 49- Cyrena conjuncta Deshayes. 
Cyrena conjuncta Desh., 1854. Proc. Zool. London XXII. p. 18. 
— — Prime, 1869 — 70. Catal. Corb. Gen. Cyrena Nr. 16. 
T. orbiculato-trigona, crassa, solida, ventricosa, subaequilaterali, utraque 
latere obtusa, rotundata, interne regulariter arcuata, margine antico supe- 
riori declivi, rectilineo; postico convexo; epidermide viridi - fuscescente. trans- 
versim regulariter tenue lamellosa vestita; umbonibus tumidis, obliquis, bre- 
vibus, obtusis, erosis; ligamento brevi, angusto, immerso; valvis intus albis; 
dentibus cardinalibus tribus, inaequalibus , postico valvae dextrae latiore, 
inaequaliter bifido, mediano eminentiore, acuto, profunde bilobato; dentibus 
lateralibus parvis, distantibus, antico eminentiore, conico, compresso. 
Hab.? (Desh.). 
Nr. 50. Cyrena Cumingii Deshayes- 
Cyrena Cumingii Desh., 1854. Proc. Zool. London XII. p. 22. 
— — Prime, 1864. Catal. Corb. p. 6 und 1869 70. Gen. Cyrena 
Nr. 18. 
T. ovato-subtrigona, inaequilaterali , tumida, cordiformi, satis solida, 
transversim inaequaliter tenuissime striata , epidermide fusco - virescente , in- 
ferne lamellosa vestita; umbonibus magnis, prominentibus, oppositis, decor- 
ticatis ; approximatis ; latere antico brevi, late rotundato, postico attenuato; 
superne declivi, extremitate truncato, angulo obtuso decurrente circumscripta ; 
cardine angusto, in medio paulo latiore; dentibus tribus primariis inaequali- 
bus, approximatis, angustis, apice profunde bifiidis; lateralibus magnis, 
aequidistantibus, antico paulo majore, conico, acuto; valvis intus candi- 
dissimis. 
Long. 60, lat. 52, er. 44 Mm. 
Hab. America centralis. (Desh.). 
Nr. 51. Cyrena decipiens Deshayes. 
Cyrena decipiens Desh, 1854. Proc. Zool. London XXII. p. 17. 
— — Prime, 1869 — 70. Catal. Corb. Gen. Cyrena Nr. 21. 
T. ovato-subtrigona, tumida, inaequilaterali, parum crassa, epidermide 
viridi, lamellis transversis distantibus, crispis instructa vestita; lamellis po- 
stice multo numerioribus , appressis, erectis; umbonibus minimis, decortica- 
tis, vix obliquis; latere antico breviore, superne convexiusculo , declivi; in- 
IX. 3. 30 
