ANALYSIS OF SPECIES
| Striæ interrupted by a hyaline furrow on each side of the median line | kinsmanii |
| Striæ not interrupted: | |
| Loculi, five, or less | exigua |
| Loculi, more than five, equal, ending at distance from the ends | smithii |
| Loculi, ending near the ends, distinct | lanceolata |
| Loculi, ending near the ends, indistinct | elegans |
| Loculi, very numerous | apiculata |
| Loculi, unequal | angulata |
Karsten states that there are two chromatophores, each of which extends from the middle of one valve to the end and down the middle of the other valve. Mereschkowsky says, however, that there are four plates or chromatophores, sometimes on the valve, sometimes on the zone, according to the species, and that two long pyrenoids unite the two opposite chromatophores.
MASTOGLOIA KINSMANII LEWIS
Valve lanceolate-elliptical, with sub-rostrate ends; loculi more numerous than in M. angulata but less than in M. apiculata, the middle ones larger. Median line with a sulcus on each side; central area quadrate.
Mastogloia braunii Grun. (According to Cleve).
Atlantic City.
Pl. [17], Fig. 16.
MASTOGLOIA EXIGUA LEWIS
Valve elliptical- or linear-lanceolate; loculi, 2-5, usually 3, larger in the middle and rounded; central space small; striæ, 20-24 in 10 µ.