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) SHUiichrasti (Crosse 

 and Fischer) (1872). — Five specimens: i adult, bleached shell 

 from the burnt-over area (H, II, a) ; i 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, II, b) in the lowland 

 j ungle. 



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 



