Transcriber’s Note:
The cover image was created by the transcriber and is placed in the public domain.
| $2.00 per Year. | ($2.20 to Foreign Countries.) | 50 cts. a copy |
| EDITORS AND PUBLISHERS: | ||
| H. A. Pilsbry, Special Curator of the Department of Mollusca, Academy of Natural Sciences, Philadelphia. | ||
| C. W. Johnson, Curator of the Boston Society of Natural History. | ||
| Vol. XXXI. | OCTOBER, 1917. | No. 2 |
| Notes on the variation of Ischnochiton conspicuus. By E. P. Chace | 37 |
| Lampsilis ventricosa cohongoronta in the Potomac River. By Wm. A. Marshall | 40 |
| Collecting about Guantanamo Bay, Cuba. By John B. Henderson | 41 |
| Amnicolidæ from Oneida Lake, N. Y. By H. A. Pilsbry | 44 |
| New Genera and Species of Central American Naiades. By L. S. Frierson | 47 |
| On the rate of growth of pond Unios. By L. S. Frierson | 49 |
| A new South African Nesopupa. By H. A. Pilsbry | 50 |
| A new Gundlachia from Guatemala. By Bryant Walker | 51 |
| A list of shells from the East Coast of Florida. By Bryant Walker | 53 |
| Collecting in Digby, Nova Scotia. By Lilian Dyer Thompson | 57 |
| A new type of the naiad-genus Fusconaia. By A. E. Ortmann | 58 |
| The Relation of snail fauna to floods. By A. Richards | 64 |
| William Bullock Clark | 68 |
| Publications received | 69 |