MACTRA. 55 
to the figure of Chemnitz (Conch. Cab. vol. vi. pl. 20, f. 199, 
200), whose specimen was also received from Lorenz Spengler. 
The authenticated locality is correct. 
Slactva plicatarta, 
The Mactra plicataria (Chemn. Conch. Cab. vol. vi. pl. 20, 
f. 202, 203, 204) of authors still remains in its marked re- 
ceptacle in the Linnean cabinet. The shell, being strongly 
characterised, was recognised by conchologists without diffi- 
culty. 
Mactra strvtatula. 
This Mactra still remains in its marked receptacle in the 
Linnean cabinet, and correctly agrees with the characters 
attributed to it. Not being able to discover any exact por- 
traiture of it, nor to assert with absolute certainty that it has 
received any modern appellation (it nearly approaches the 
angulifera and angusta of Reeve’s Monograph of Mactra, but is 
pronounced distinct by that eminent authority, Mr. Cuming; 
it also reminds one of the M. Californica of Conrad, Journ. 
Acad. Nat. Sc. Philad. vol. vii.), I have given a figure (pl. 2, 
f. 8) and an enlarged description of it in the present work. 
Macrra striatuna, Lin. (haud auctorum). Testa ovali-sub- 
trigona, tenuis, convexa, subpellucida, subzquilateralis, alba, 
precipue sublevigata, umbonibus tantum subplicatis. Latus 
anticum paullo longius, subangulatum; extremitas postica 
rotundata. Margo ventralis convexus; dorsalis, postice satis 
declivis, et prope nates acutas subretusus, deinde convexius- 
culus, antice subrectus et valde declivis. Costa umbonalis 
antica carinata; areola subexcavata: lunula subobsoleta. Long. 
1, lat. 1°6 poll. 
