- 
THE NAUTILUS. 105 
Presidential Address—The Armature of Land Mollusca. By 
G. K. Gude, pp. 52-73. 
Note on Xylophaga praestans Smith. By J. R. LeB. Tomlin, 
p. 73. 
Concerning Edenttellina. By Charles Hedley, pp. 74-76. 
E. corallensis n. sp., p. 76, figs. 6-8. 
Nomenclatorial Notes Relating to British Non-marine Mol- 
lusca. By A. S. Kennard and B. B. Woodward, pp. 77-90. 
The Anatomy. of two species of Helicarion from Tropical 
Africa. By Hugh Watson, pp. 91-118, pls. 3&4. H. crypto- 
phallus n. sp., p. 97, pl. 4. 
Mitra burnupiana n. sp., from South Africa. By Rev. A. 
H. Cooke, p. 114. 
Note on the dates of publication of the earlier parts of Cap- 
tain Thomas Brown’s Illustrations of the Conchology of Great 
Britain and Ireland. 2nd edition. By Alexander Reynell, 
p. 116. 
CORRELATION OF SHAPE AND STATION IN FRESHWATER Mus- 
sELS (Naiades). By A. E. Ortmann. (Proc. Amer. Phil. Soc., 
1920, Vol. 19, pp. 269-312.) The author has ascertained 
‘‘that the more obese (swollen) form is found farther 
down in the larger rivers, and passes gradually, in the upstream 
direction, into a less obese (compressed) form in the head- 
waters; with the decrease in obesity often an increase in size 
(length) is correlated; a few shells which have in the large 
rivers a peculiar sculpture of large tubercles, lose these tubercles 
in the headwaters.’’ The observations were made in the head- 
waters of the Ohio and Tennessee Rivers. 
VARIATION IN NacreEous CoLor oF CERTAIN SPECIES OF NAIADES 
INHABITING THE UPPER OHIO DRAINAGE AND THEIR CORRESPOND- 
Inc’ ONES IN LAKE Erie. By N. M. Grier (Amer. Midland 
Nat., 1920, pp, 211-243, Vols. 2-3). In a summary the author 
says ‘‘In practically all the species dealt with a change in 
nacreous color is observed going down stream from the head- 
waters to the mouth. . . The shells of L. Erie have a greater 
