58 University of Michigan 
developed.) The expansions of the laterals are entire, except 
that in one or two cases the outer wing was apparently slightly 
angulate. A definite ectocone is developed on the tenth tooth, 
but the entocone remains vestigial out to about the twelfth. 
The teeth just beyond the tenth are more elongate and have 
shorter bases than any of the others. The remainder of the 
definitive teeth are tricuspid, but the outer ones are variable, 
and may have as high as 5 cusps. The thirty-first is a mere 
denticle. 
Averellia (Trichodiscina) suturalis (Pfr.) (1846)—Two 
young specimens appear to be this species; one from the 
ground in the lowland jungles (H, I, a), the other under chips 
of bark on the ground in the savannah forests (H, III, a). 
Averellia (Miraverellia, new subgenus) sumichrasti (Crosse 
and Fischer) (1872).—Five specimens: 1 adult, bleached shell 
from the burnt-over area (H, II, a) ; 1 specimen (almost adult) 
and a juvenile from under logs on the ground (H, II, a), and 
2 juveniles from the bark of a tree (H, IJ, b) in the lowland 
jungle. 
This is a flattened, subangulate species, with the last whorl 
sharply descending near the aperture, as in most species of 
this genus. As Crosse and Fischer have pointed out, the whole 
surface of the fresh specimens has low, but prominent, cres- 
centic to lanceolate excrescences, which extend parallel to the 
growth-lines. These are interspersed with more numerous, 
minute, conical projections, so that the entire shell appears 
setose under the lens. This sculpture reaches to the apex, but 
is more minute on the apical whorls, so that they appear 
smooth, by contrast, to the naked eye. These projections super- 
ficially break the regularity of the growth-lines, so that the 
epidermis appears marked with anastamosing wrinkles, which 
