Valves without costæ; striæ moniliform; upper valve with excentric pseudoraphe or median line; otherwise as in A. longipes.
Along the coast, in estuaries.
Pl. [16], Fig. 3.
ACHNANTHES SUBSESSILIS KUETZ.
Valves linear-elliptical, rounded at the ends; upper valve with excentric pseudoraphe; striæ moniliform, puncta smaller than in A. brevipes.
Along the coast, in estuaries.
Pl. [16], Figs. 4, 5, 6.
The three species described above are named from the length of the stipe, but this varies considerably and is not of special significance.
ACHNANTHES INFLATA (KUETZ.) GRUN.
Valves more or less inflated in the middle, usually with the stauros of the lower valve asymmetrical and wider than in A. subsessilis, with which it agrees in size and markings.