Occasional Papers of the Museum of Zoology 57 
M. Almost discoid in shape: 4; 62; 4. hornti (Gabb) 
MM. More elevated spire: 4.5; 78; 5. wmpura ( Pir.) 
LL. Entire shell with beaded appearance, a few of the radial 
folds may be developed into higher riblets. 
N. Shell larger and more depressed. 
O. 3; 83; 4 (type Microconus). wilhelmi (Pfr.) 
OO 3470 ae cockerellae Pilsbry 
NN. Shell small; Pupisoma-like; texture like “fine woven 
material.” 1.95; 100; 4%. textilis Pilsbry 
HH. Apical whorls without definite spiral striations, but with regu- 
larly spaced, smooth, well-developed riblets, parallel to growth- 
lines. 
P. Larger species; slight tendency towards spiral stri- 
ations. 3; 60; 3%. tatet Pilsbry (blakeana Tate) 
PP. Small species; minute striations between ribs, 
which form oblique squares, 4 microns across. 
NSS Ate Sie pilsbryi n. sp. 
Averellia (Trichodiscina) coactiliata (Ferussac) (1838) .— 
Seven specimens; from leaves and bark of trees in lowland 
jungle (H, I, b). One of these specimens contained the dried 
remains of the animal, and from it the jaw and radula were 
obtained. 
The arcuate jaw (fig. 9) bears 13 broad, low ribs, but is 
also striate so that the ribs appear rather irregular and indis- 
tinct. The radular formula (fig. 7) is: 
I 9 07) 4 I 
>-L—;M— + — + —;3or 3I-I-31. 
1-3 1 See 9) I 
The central and the inner nine laterals are functionally uni- 
cuspid, but the rather long and slender mesocone bears lateral 
Cc 
expansions or wings on both sides, below the level of its cut- 
ting edge. In some of the centrals, each of these expansions 
has a rather blunt and very indistinct cusp, which is only vis- 
ible under the oil-immersion objective. (On other centrals I 
was unable to detect these, and suspect that they are not always 
